all i have had a chance to do with this is call and talk to some fuel system folks and test my pump and regulator at cool idle. everything checks out. the fuel system guys all say cavitating fuel and vapor locking. they all suggested better fuel.

i started thinking i used to run the car with a blend of sunoco gt 100 and 91 pump gas when i first got it till i got it tuned. and since i started running just 91 pump gas i have been having this problem.

i went to a race gas store and bought 5 gallons of 101 octane to mix with the 91 pump gas thats in the tank. im going to run threw that this week and put 91 with no ethynol in the car. i dont mind going to the 91 no ethynol or even a 91 no ethynol blend with 101 if it makes the car run right. the guys at the station also said the ethynol has given lots of cars fits with vapor locking.

the 91 no ethynol is 4.10 a gallon. biggest issue is i cant pump it directly into my car. stupid laws if it was a 76 or older car i could but being a 91 i have to put it in a gas can. oddly they will let me pump the 101 right in there.

101 is 7.98 a gallon. so blending this is the only way im not going to pay 8 dollars a gallon.

ill let you guys know what happens. i did read in the thread some folks were suspecting the ethynol in the gas.

 

Had the problem last summer. Nothing all winter. Now I sit here on the side of the road after she died and will not start. Frustrating. How are the guys in the Northeast doing during the heat wave?

All this was with a full tank of gas and about 40 minutes of driving time in 95-99* heat. I say I had the problem last summer but have actually seen it since I moved to TX from CA in '07. Tried to drive from Ventura County and made it about 90 minutes in LA traffic before it died. Since then I added a new fuel pump (Walbro) and nothing but 89-92 octane gas. I noticed the boiling gas after changing to the Walbro but I lived on the coast in CA and it rarely got above 85*.

Anyhow, after I had it towed home it started and ran about 30 seconds, ran rough for a few seconds after and then died. Went inside to cool off (mentally) and then went back to it. Attached fuel pressure gage and accessed the fuel pump relay to take voltage readings during prime (~12.8V) and while running (~13.6V). Started it up and it ran with noticable fuel pump whine but at 39 psi (vaccuum attached) for about 5 minutes then pressure dropped to about 10psi. Repeated this 3 times and took temps of the fuel rail (140*F) and tank (111.5*F). Went in to eat dinner and let it sit for about 20 minutes. Started it back up and all voltages and pressures were good. I actually heard the fuel pump stop and then the car stumbled and died. There was definite pressure in the tank, but not excessive like I have seen in the past. Checked the canister valve as mentioned earlier and it is operating as designed. No flow until a vacuum is applied.

Now ordering a fuel tank sending unit (AC Delco) and a Racetronics fuel kit with hotwire because I don't want to take the tank out again (this will be number 4). Also order a new coil since it's old. Will blow all the lines and do something with the return line in the tank so it doesn't get picked back up by the pump immediately. Any other recommendations for the tank, sending unit and pump? Other electronics that may need replaced?

My heart will not let me get rid of her. But since I don't drive her in the winter and CAN'T drive her in the summer I need to do something...

 

I almost forgot. When I purged the fuel pressure gage to disconnect it, the last 5 psi was nothing but air...

 

Subscribed. I'm replacing fuel pump due to low pressure (but good volume). Usually run on 87 octane no problem in S. Florida heat/humidity. Crusing the temp is usually around 160. Summer in traffic w/AC goes to 200-220. These are low numbers compared to factory specs from what I read. New rad, not sure about the therm but I'm guessing its a low temp one. Once I get it back together I'll report back.

 

i think im having the same thing but i had a new fuel pump put in last year and the guy that put it in broke the neck of my gas tank and my car still runs like **** when its in the 90s

 

I got all the parts: sending unit, hotwire kit and Walbro pump from Racetronics and a fuel filter. Tore the rear end out of the car and dropped the tank, ran the hotwire kit, blew out the lines, replaced the filter and went to install the pump but I think Racetronics sent the wrong pump. Its a GSS294M as stated on the box and has a large pickup centered on the bottom. It should have an offset pickup to fit the mount on the sending unit. I have an email out to them asking what direction I should go with it.

OTHER THINGS I FOUND...

The white valve (rollover valve?) mounted on the inside of the sending unit was frozen solid. It is stuck in the up (closed) position when I compare it to the new one and could not get any air through the line. Tried to hit it a couple times and it would not budge. The new one moves freely.

Also, I had a Walbro with part number ending in 169 and date code of 15807-2 (June 7, 2007) so I may have had a bad pump also. By the way, I only put about 900 miles a year on the car so it could have taken me this long to find a bad pump... I did use it to pump out about 5 gallons of gas though.

Charcoal canister valve tested good and the canister shouldn't go bad unless it's full of gas. Any alternative opinions on the canister?

Until I find out about the pump, I guess I just wait...

 

My car recently started acting worse. I can barely drive 30min before it dies. I tried a known working fuel pump relay with no change. My crank times have been getting very long as well so I jumped the relay and let the pump run with the engine off. I held a screwdriver and rag over the Schrader valve and it took nearly ten seconds to build ANY pressure at all. When I cut the pump off and checked the rail there was no pressure at all! I pulled the fuel pump out (thank God for the trap door mod) and the first thing I noticed was the fuel hose nearly hanging off the top of the pump!! Apparently the fuel hose that I put on shrank nearly an inch and a half! The hose clamp impressions were way above the nipple on pump outlet. Pretty sure this is my problem, but I'm hoping that the pump wasn't overworked due to the issue. I bought new hose, fuel sock and filter. I'm also going to blow out all the fuel lines including the fuel rail and sending unit to make sure there are no blockages and fuel can flow freely. Hopefully this fixes everything, but I did pick up an entire LT1 sending unit with bucket and pump that I will modify to work. Last, I will install an LT1 fuel tank if all else fails. I'll try and keep you guys updated!

 

Finished the install. The pump is the correct model when used with the rubber mount Racetronix supplied in the kit. I had so many rubber mounts lying around, I had to go back and figure out which one they supplied!

Anyhow, finished the install and put about 6 gallons of gas in it. Ran it for 35 minutes. Let it heat soak for 25 and then ran it for about 10 more minutes. While the pump was noticeable, it did not waiver or wail like the old one did. Went and filled it with gas and I can't hear the pump at all except on prime before the engine starts and then I have to listen for it.

I did smell gas fumes quite a bit before I filled it up. Traced it to the pressure relief valve that comes off the tank. Actually heard the hissing when it opened. Also had some pressure built up when I took the gas cap off. Didn't notice the fumes after I filled it up.

BUT, It didn't stumble and die. Since it died with a full tank after 30-45 minutes of drive time, it is probably better. However, I will withhold final judgement until I drive it for a couple hours on a 100 degree day.

 

Have any of you replaced the piece that connects the pump to the fuel line. I don't know what it's called but its plastic with rubber seals inside. if this is bad I can see how high temps could cause fuel pressure drop and why it would not hold pressure like it should.

 

So I went under my car today. I'm getting ready to swap my rear. Looking at the fuel lines I see 4 lines one return one feed that goes through a metal filter one that goes to a little plastic deal and the 4th one has a bolt capping it off. I'm assuming its supposed to go somewhere unless it needs deleted with the lsx swap but I don't recall reading that anywhere. Anyone know what that hose should go to. And could that be causing my issue.

Thanks

 

The fourth hose is supposed to go to the canister , that directs fumes to the throttlebody .
Did you test driving with the no ethynol ?

//Christer

 

Yes I have not had an issue with it since. I went 100 miles the other day but it was only like 85 out.I also did three runs in 96 heat and drove it to work about 8 miles each way twice. The heat has moved out for now but when it gets hot again ill test it. I'm running 91 with no ethynol and I use 100 sunoco gt at the track. Might be a bandaid but I want to fix it . Hard for me to drive to far in 100 plus since I have no AC. I have to put 3 to 500 miles on my new rear end to break it in so that should be a good test. I have not done my fuel pump or wiring since everything checked out OK on that.

 

I finally received my GM Service Manual so I checked the canister, canister solenoid and Tank pressure control valve (seen it called a purge valve here). All are operating normally and I no longer have fuel vapors coming from the rear pressure relief valve. Maybe something inside the valve was stuck before. According to the manual it's a pressure and vacuum relief valve that passes vapors when pressure exceeds 1"Hg. I'll replace it anyhow as cheap insurance in case it was failing before causing the excessive tank pressure. Going to drive it this weekend until I get tired or it dies. Supposed to be well over 100* so wish me luck.

 

Good luck man its 100 here and I drove to work in the camaro. Took my kid home and then to work so maybe 15 20 miles about 30 minutes running. No issue but when I pulled the gas cap I had a ton of pressure. Every time I drive it it builds a good bit of pressure. I'm going to try a vented cap and eventually put the canister back in. I think that line being blocked off may be my problem.

 

Funny that you mentioned that. I took out a section of my PDF GM Camaro Shop Manual and posted up the whole testing and troubleshooting of the EVAP Canister system, along with pictures. But in my case it's the same noise but with very different conditions. If I'm low on gas, I get the noise as soon as I turn on my Camaro, in the morning, in 40* weather, in December. So there is no time for my fuel to heat up or pressure to build up. So what could my issue be? I say just a bad fuel pump to begin with.

 

I’ve followed this entire post and there has to be at least two different problems going on here for sure, probably more. I’m sure a lot of it is bad fuel pumps, but I’m also sure that some of you are actually having evap system problems because once I found out what was broken with that system, it cured all of the symptoms listed below.

1. Idle too low
2. Engine would die at stoplights
3. Incredible pressure in the gas tank, only relieved by removing the cap
4. After some time, a very loud humming/whining sound coming from the gas tank. This sound is almost like a fog horn sound and comes from under the back seat The sound would continue with the key off, and would stop when the gas cap is opened and the pressure released

My evap system repair write up is here:

https://www.thirdgen.org/forums/tbi/657593-solved-excessive-gas-tank.html#post5332739

 

Here's my testing of the evap system.
https://www.thirdgen.org/forums/tech...-solenoid.html

 

69Z11 and Chevy86, I also used the GM Service Maunal to test my evap system. It's a little different since mine is a 91. Canister holds a vacuum until I ground the diagnostic port (solenoid is good). Pressure control valve held vacuum, DID allow air through when the control port had vacuum, and it allowed air to pass with some pressure behind it from the tank side (valve was good but replaced it today anyhow). Only thing left is the canister and the manual says if it holds a vacuum it's good. It's not full of gas either. Oh, and the car runs perfect. No misses, no surging idle, no rough idle. It runs as smooth as my wife's Infiniti.

Here's what I had today...

Put in the new canister control valve. Drove for 90 minutes and had it heat soak for another 30 minutes after the first hour. On my way home and when I was at a stoplight, I could smell fuel vapors. Could smell nothing driving down the road. When I got home, I smelled no vapors from the rear of the car but had a ton of vapors coming out of the air port of the canister. This port is supposed to be used to take fresh air in when the solenoid opens. Opened the fuel cap and had pressure that didn't seem to want to stop and the car was shut off. When I put the cap on to the point just before it seals, it would sit there and hiss. I let it go for three minutes and it was still going. I think I was right on the verge of boiling the gas

Since the air port is supposed to take air in, I will assume the canister is bad and attempt to find one and replace it. That's the last part of my fuel system that isn't new except the lines and hoses (which are clear and don't leak), the tank (which obviously doesn't leak) and the fuel rails. Chevy dealer is closed until Monday so I'll let you know what happens then...

 

Wow. You have really gone from point A, almost down to the end of the alphabet. Im curious to know what you find.

 

Canister ordered. Will receive it tomorrow and install. Then I'll drive it until it dies, I smell fuel or I get down to 1/8 tank since I see the problems most below 1/4 tank.

 

Good luck man I'm hoping it is cured after this.

It appears thatvi have bandaided mine but I will be attempting to rebuild my evap system that was removed. I'm pretty sure that is the route cause of my problem.

 

Any out of tank fuel pump suggestions?

 

New canister in (GM Part number 17092109) whcih also came with a solenoid. Had quite a bit of hot air escaping the same air port, BUT NO FUEL VAPORS. Drove it for a couple hours and it's just over 1/4 tank now. No boiling gas, no fuel vapors anywhere and the tank had pressure like it should without wanting to blow the cap off in my hand. Outside temp was right at 100* today. I feel comfortable my issues are resolved, but will drive it around the neighborhood for a while to make sure it doesn't die after operating at 220* for a while. Here is the list of parts that were replaced and why with part numbers in parens (for a 91 Z28 5.7):

1. Racetronix Fuel pump and Hotwire kit - Fuel pump was whining after about an hour of driving or when it got hot
2. Fuel Tank Sending unit (19111386) - frozen rollover valve in the closed position (Also replaced the sending unit lock ring (25124032)
3. Canister pressure control valve (17087240 but From Oreily's Auto Parts) - Wasn't venting the tank to the canister when under pressure. Caused the tank pressure relief valve to open causing fuel vapors in the rear.
4. Canister (17092109) - Fuel vapors escaping from the air port when idling
5. Fuel filter - because I was there and it's cheap and easy.

I had multiple issues that added to to a large headache. Will keep you posted if anything else happens.

--Edit--
Drove it more today during the heat of the day and got down to 1/8 of a tank with no issues.

 

Welp I just Moved from maine to NC and I got stuck in traffic in the Tunnel in boston and I swore it was a mack truck's brakes behind me.... then after that it was all open road till I got to NC off I-77, and hit the traffic lights then the Whining started in very very loud. I filled up my tank 11gallons, and it was quiet for the 40min ride to the apartments im at.

The next day i went out job hunting, and the damn thing started howling after an hour of driving, i had the A/C cranked so the heat from the condenser isnt helping. But I'm so close to changing the fuel pump. It runs perfect till its been sitting at stop lights and such, then the pump whines... I had it run rough and shut off on me once.... cylced the key a few times and it started up i took it to get fuel, and filled it again 11gallons, and it was quiet another 40 mins to the apartment....

while i was filling the car i popped the hood felt the lines and i couldnt hold them for very long. Very hot gas. so i dont know what to do. It never did this in Maine. and it gets 85* in maine not 104*. and we dont have near as many stoplights... Its all open road....

 

Sounds like its "just" a fuel pump as long as you don't have any of the other symptoms. Mainly fuel vapors at the front or rear of your car, rough idle, or what sounds like boiling gas in the fuel tank. My tank still runs hot and the fuel rails are Almost too hot to touch after driving for a while.

 

yea mines 3.1L auto. not a v8 like you guy's. but same problem. the fuel lines under the car are even hot as heck.

 

Welcome to the hot, southern US!

 

Nothing like the Yuha Desert here in the deep "SoCal" where I'm from. 107* summer averages. Funny thing is that I never stall in my Camaro, even with the howling pump.

 

hahaha yea this is true!!! I dont know what to do. i swear the Fuel pump is fine. I am 99% sure its the heat, but how do i beat the heat?

 

I don't. I have all the same syptoms as everyone else but a little different. During the winter, on a cold start, my pump whines straight off the bat. It only whines when I'm low on fuel. But my fuel can be ice cold and the pump will still whine. So I don't know what the deal is with my pump. But like I said, on a hot day, it'll whine and howl really loud but I'm fortunate that mine doesn't stall.

 

http://www.jegs.com/i/DEI/186/080120...rentProductId=

Would this work? It seems like it'd keep the gas cool lol i just dont know how it works.... liquid c02.... does the heated gas make it get colder?

 

Mine doesnt whine or howl till the motor is at 200*ish and im in traffic.

 

The pump I had in would do the same. And it got worse this year. Last year I could drive a while but the gas would boil and the pump would start pumping air after about 90 minutes. This year it was an hour and the fuel never got to the boiling point. When you add fuel, the pump cools down and you are good until the fuel heats back up. If you have a big box auto parts store fuel pump that is more than a few years old, it's probably time for a new one. If it's original, you're overdue.

 

I've never seen that! I would assume that it does work to help cool off the fuel. I wonder what the community would think.

GUYS!!! Got any opinions about the product?

 

welp i did the dirty work. I asked a tech at jegs. Im curious if they require Co2 all the time or if they are a contained unit... if theres no maintenance needed Im getting one. I dont know if i need it on the return or the pressure/input side..... I'd think the gas in the tank is cool enough to make it to the motor. its the returning with all the heat thats screwing me/us.

 

Yup. It should be installed on the return line. Now I'm very interested. Perhaps this is the miracle cure. Funny that in my GM shop manual, it says the the design of our TPI fuel rails are supposed to cool off the fuel. Go figure. Hahaha

 

I have checked, the 186 080120 it is a sealed unit. There is no maintenance or service needed for this part. He said it would work great to keep the fuel cool in the tank on the return side and this can be used by itself unless you want more cooling capacity, but what i need this for, it will be just fine. So I'll order one and get it in about three days. I just need to find out what size my Fuel lines are under the hood by the motor. and Mines the v6, who knows if they're diffrent from the v8's

 

I don't think this is what you are looking for:

http://www.designengineering.com/con...get-more-power
http://www.designengineering.com/sit...main-large.jpg

It requires a flow of CO2 to chill the fuel.

RBob.

 

Thats a super kit. I just want the fuel bar.
http://www.designengineering.com/cat...genic-fuel-bar
http://www.designengineering.com/fil...yo2fuelbar.pdf

supposedly the Bar can be used alone and chill to -80*f.

 

After talking to DEI, He said it works just like a NOS system, it doesnt work without the bottle. and it wont work for very long trying to cool fuel for traffic condition's, the Co2 would deplete. which if you read their description the do a good job of selling things haha. so no this wont work and thats all out of the question. MYTH BUSTED!!!!! however, if you run your low side a/c through the Co2 ports.... you'd do plenty of cooling ahahhahahaha

 

Well, Either i found a fix or its just not hot enough. Its 90*f Here in charlotte NC. Sunday I Bought and installed http://www.autozone.com/autozone/acc...er=953383_0_0_ remember mines a v6. Not sure how the TPI lines are routed.. I Wrapped the lines from the trans to the Intake, Even the foot of the rubber hose. But Not under the plenum. Used Zip ties along the way Just in cause this stuff sucks and looses its stick. after driving an hour north, and coming back, i hit every da** red Light on my way back. and not One Hum or stumble. Gaaahd i hope this is the Fix. I also took notice of the temp of the lines running up the Uni-frame near the Exhaust... WOW surprised Gm didnt have these issues back when these cars were new. Was there a Heat sheild on the manifolds thats gone missing over time? I know the corvettes had a Complete sheild around the manifolds. but as we all know over time they rust and rattle and get taken off.

 

Heat shield for the fuel lines? Good question. Never heard of one.

 

C*N7. its def helping.. but i got stuck on 85 North bound for about 2hrs had half a tank and WOOOOOOOT WOOT WOOOOOOOOOOT WOOOT. but it never died..... man this really blows

 

Just because I thought this would help people who are wondering - i have an 87 5.7 TPI. Due to issues with the FP gauge, and because the fuel pump had about 50k on it, we replaced the fuel pump, sending unit, floats and all. With an AC delco OEM pump from a reputable parts dealer. We had done a couple other things to the car at same time, and when i started driving it, suddenly, i had a heating/stalling issue. The car would be fine cold, but driving in traffic, it would heat up and suddenly start choking and stalling. NEVER had this issue before. We actually put in a 4 core aluminum radiator, still same issue. It wasn't until I took it out for a major test drive, that we found the problem. I ran it out on interstate for 30 mins, at 75mph, 90 degrees air temp, with the A/C running. Ran perfectly! A/C going, cool air, car temps were fine. Got off interstate, A/C still running, car still fine. Thru stop and go traffic, no problem. I'm happy! Got out on back road, and got hung up in construction traffic. Well, i wasn't going to SIT with the A/C running, so i put her in park, rolled down the windows, and waited. Temps got up to the 220 mark, fan kicked in, and then she started wanting to stall. Crap. Well, traffic got moving, got car up to speed, and away we went. Temps went down, all is good. I'm puzzled. I had noticed a funny noise, but wrote it off to all the contruction equipment. Well, 8 miles down road, more construction! And same thing happened! HEats up, tries to stall. And this time the 'train whistle' noise is MUCH more apparent. Every 5 seconds. whoooOOOOooo. 5 seconds on, 5 seconds off. A/C not running, so I know darn well its not the compressor. Got out of traffic, up to speed, cooled off, got it home again. Pulled into the driveway and popped the hood. Odd.... No noise? Not coming from engine? Walked back to drivers door, could hear the noise, and realized it was coming from BEHIND me. Oh, crap. Yup, its the fuel pump! I've had this car for 150K, its never EVERY had this issue before. And yes, I live in colorado at 6500ft in altitude, where they run 10% plus ethanol in the gas ALL THE TIME! Highest octane rating you can get out here is 91. I run 87 and never EVER had an issue. So folks, I HAVE to conclude, ITS THE DAMN FUEL PUMP!!!!! And i got a bad (or heaven help me they are ALL crappy now) out of the box pump. We are looking for a replacement, its a fairly stock IROC so i WANT to go with the stock pump, but now, not sure what to do. Maybe they are all made in china junk now????

 

Wow. But the issue still is up in the clouds. The big question is;;;;; what is causing the Fuel Pump to whine to the point that stalling is emminent.

What happened to the guy who put a fuel pump in a bucket? I think he was from Ft. Collins, CO.

 

well I went for a ride this morning, it was 70* and I had no issues. Got back home, it was pushin 80. traffic and all. and not a peep or a stumble. I can honestly say Its not the fuel pumps..... yet.... if we keep having this issue its bound to burn out the pump(s). The Pressure regulator. No. Its all heat bound. and My question is Does the Ethanol blended fuels evaporate at a lower temperature? as far as the Gunk in the tank gig.... the Sock is there for a reason and I believe it would be a constant issue, not just when hot in traffic. Now dont be getting all dirty minded here. Everytime i top off when the tank is WOOOT'n I stick two fingers in the Filler neck, and Its F*#&N HOT in there. Hot enough to burn. and I can hear Bubbling when i put my ear to the Filler neck.

yes this sounds like the pump is getting HOT and causing the fuel to boil off the pump. but we wouldnt be sucking air off the side of the pump... Could the Fuel be boiling off the bottom of the tank thanks to the muffler?? Im Currently Reading
http://en.wikipedia.org/wiki/Gasoline

 

I've got a Racetronix hot wire kit in the mail, and also bought a new sending unit because the vent line on the top is cracked, so hopefully this solves my stalling issues. Last time I drove the car in May it stalled out on me while driving 30 minutes to the garage I stored it in. I will update after the install if it worked for me. I'll probably test my EVAP system also as that seems to make a big difference.

 

I Havent done anything to mine since the Heat tape on the lines... and It still howled that week it was 105. but today its 85*f. I did my regular routine and did some touring through the City and it didnt even try to Howl I dropped the fuel level to quarter tank. So now i feel confident its the heat. I get my gas at the same station everytime, as i cross the border to SC and get gas 50 cents cheaper... I have no idea why people are lined up in NC to get gas at 3.75
/gal three miles away you can get it for 3.25/gal................

 

Well, I'm glad to report that I've fixed my car's issues. I was having the same issues (whine, back pressure, stalling, lean, had to wait a few minutes to cool off, etc) after the engine swap from stock 305 to 350 and installing a cheap Airtex FP from Auto Zone. The only difference is that I had not hooked up any of my vaccum lines except the PCV. After reading this for several days last week I decided to blow some air through the line from the tank to the canister and install all new vacuum lines. That solved my problem! Only thing not hooked up yet is my EGR, 'cause I can't find the electric connector to the solenoid behind the engine somewhere. I'll be replacing my injectors soon so I'll look for it then when I have more room to dig in. My engine is stock, no headers either, except what's on the signature, which does not affect the FP at all. BTW the PO had removed the heat shield between the tank and the muffler when he replaced the FP 10 years ago and I didn't realize it until I replaced it myself. I hope this info helps some of you.

 

Well, I finally believe I know EXACTLY what is causing the heating/stalling issue. Finally! I recently had my Iroc dyno'd down in Georgia and while I was there I had them adjust my timing and fuel pressure to get the best run possible. Put down 215rwhp, 305 with a small .471 lift cam, headers, and cat-back! Well immediately after that my car started having the heating/stalling issues (even though my car never goes over 190* even in traffic). So I pulled the pump (thank god for the trap door mod!!) and found that the rubber fuel line coming off my Walbro 255 had shrank by almost an inch and was sitting on top of the pump outlet! I couldn't believe it would crank and drive! I believe the ethanol mixed in today's fuel had something to do with the massive shrinkage. So I put a new "longer" fuel line on the pump and new sock. I put it all back together thinking I've got it all fixed, but the problem was still there! No change at all!! So I pulled everything back apart. Pulled the fuel filter. Pulled the lines off the fuel rail and blew compressed air through all the lines. This is very messy so be careful. When I tried to blow out the fuel rail, I couldn't get any air to pass through at all. Hmmmmm.... If air can't get through, how can fuel?? Then I started thinking maybe my new BBK adjustable regulator was bad. So I hooked all the lines back up to the pump and fuel rail. I pulled the connector off the fuel pump relay and jumped power to the pump. With the pump whining loudly I could hear strange noises very faintly coming from the fuel rail. So I loosened the regulator adjuster screw and WHOOOSH! I could hear all kinds of fuel flowing through the rail and the pump whine was GONE!! Took it for a test drive and OMG the power difference was amazing! But anyway, the gist of the story is that yes the fuel pump was overheating due the strain of trying to hold pressure in the system with no flow. Topping off with cold fuel allowed it to pump longer under the strain. The muffler under the tank has NOTHING to do with it (which I knew all along, come on, it's obvious!). Tank pressure has NOTHING to do with it. Too much pressure only helps the pump do it's job and reduces vaporization. Too little pressure doesn't affect anything. I had removed my charcoal canister a LONG time ago and just left the vent line open with no problems. Basically, anyone who is having this specific problem of driving fine for a little while with great power and then slowly losing power (along with increased pump whine) until it cuts off is having one of two problems, possibly both:

1. Bad pump, replace. If stock then buy el-cheapo with a lifetime warranty!

2. Partial or Full blockage of the return or feed line.

Oddly enough, my pressure was adjusted using a guage and did not spike even though the return line was nearly closed off. It was adjusted to 43psi. Either way, I have no more issues with pump whine or stalling regardless of heat. I still put a new fuel filter in and some fuel injector cleaner while I was working on things.

I really hope this helps a lot of people, because until now, I've yet to hear of anyone post a definitive cause/solution for this problem. Good luck!