I posted this up here before I know but it wasn't in its own post and the responses weren't too enlightening, mostly because I didn't give enough info. So ok, the deal is...when I'm driving the car sometimes, holding a steady speed, the car will run normal for about 4 seconds, and then lose 100-200 rpms (I'm estimating)...and the engine sounds like it's bogging down when it does this..and it does this for an almost exact equal amount of time, 3-4 seconds..then back to another normal 4 seconds of operation. It's a continuous cycle and it's done it between 30 and 45 mph so speed doesn't have much to do with it..I can pretty much eliminate anything in the drivetrain right off the bat. Plus I can HEAR the engine better with the new exhaust and I can hear whatever it is happening, the engine tone lowers and grumbles... ALSO, whether by sheer coincidence or not, I've only seen it do this, that I can remember, when I'm on less than half a tank of gas...I was thinking maybe the sump is drying out, but still 1/4-1/2 should be plenty of gas especially when I'm not jerking to the sides or accelerating/braking..this is when going a steady speed. Another detail, when I hit the accelerator during one of the bogs, the car kicks and lurches (almost feels like transmission there) and then accelerates sharply with the right amount of throttle. This is all the details I can give...I have no idea in hell what this could possibly be, so I don't expect you guys to..but hey, ya never know.. Could it somehow be my gas pickup like or pump? Maybe some sort of EGR malfunction? I really don't know...doesn't make sense to me. Thanks guys..

PS-I took my car to Family Auto Mart today to check out a 94 Formula Firebird for sale..they gave my car a $1500 trade in value! BS! I can get at least $3,000 on the street for this thing!

 

Did you check the timing, and check the inside of the distributor cap for excessive carbon tracking? Did you check the gap of the spark plugs? I wonder if you've got a misfire somewhere.

I also hope it's not the fuel pump (yikes)

Oh damn it's past my bedtime!! So much for getting in early and actually going to sleep... oops. I got the "getting in early" part right and forgot about going to sleep

 

The next time your driving and the car acts up, put it in neutral and see if the RPM's continue to fluctuate. That will help narrow it down.

 

Could it possibly be the torque converter lockup going in and out? If that isn't locking and releasing properly, it could give you the fluctuations and the shuddering. If you are sure that isn't it, then it would have to be an engine problem. Noticed anything else, like the car dying at lights, loss of fuel mileage or power?

 

Tom, I have brand new Bosch Platinum plugs waiting to go in, but I can't get the #1 plugwire boot off of the original plug. I don't have a 15 foot pair of needlenose plyers. I've tried everything...wrenches, smaller plyers, etc. It's on too tight for me to squeeze a few fingers in between the EGR and valve cover, another through the alternator bracket, and pull..tried that already. Also, I have a new cap and rotor waiting to go on...BUT I'm waiting until I get a timing light so I can adjust the timing while I'm there. So that's everything right there... Pontiacguy....the torque converter locks at 40 mph..but this happens as low as 30 or 35 and up to 45 and past probably... Also, I have a torque converter clutch switch...ties together the upper, outermost pins on the diagnostic port, which force-locks the converter..it doesn't slip out of lock at all. I've got no loss of power at all...still runs fast as crap My gas mileage is decent, and it only died on me once at a light, in which case before it did die the car was bogging down really bad between idle and 3500 rpms or so for some unknown reason. The problem isn't power..it's just the problem that I described, and that the engine's response to the throttle is sometimes inconsistent/incorrect/jerky. Now I thought about a misfire...but again...why 3-4 seconds? If it's misfiring, shouldn't it be like a rough shimmy, not 4 seconds of normal, 4 seconds of bog? I can't check the rpms directly because the tach is busted..all I can do is listen to the engine...I'll try throwing it in neutral next time but the engine revs up a tad when I do and it messes it up..it's hard for me to tell by hearing alone.

 

Wow, you really do have a booger of a problem! I would say that it could be the throttle position sensor. They are cheap and easy to replace, so I would change it just to eliminate that as a problem. My wife's 1995 camaro 3.4 liter had that go bad one time, and the only two places the car wouldn't die was either idle, which was at about 1800 RPM, and WOT. The only way I got it home was to pop it in and out of drive until I could get it to roll, and then floor it. I then would get up to about 65 MPH, put it in neutral and coast, then repeat the whole thing. You might have a dead spot on the TPS. I apologize if you have already tried that.

 

I'll have to check that out..I've been suspicious of that bugger for more than a month now. I'll call up Autozone and Discount and see how much theirs is...if they don't have the model specific kind, would the universal work or is there something weird about it I should know? If it's like you say, cheap and easy, then it's worth a shot right? Is the tps anywhere near the throttle blade? I assume it is...any wires/cables from the blade? I'd just like to know what I'm replacing..my manuals aren't always the most informative or detailed.

OH WAIT, I have no money. Guess I'll replace that in another month.. Stupid fast food job changes...

 

Bummer about the plug placement. I can get to mine nice and easy! Do you have to take the alternator bracket off to get to it? You have the straight boot plug wires, right? I wonder if on your next set, if you get right angle plug boots, if that would help things.

 

Lol yeah..I have straight boots. It's a ROYAL PITA. I can get a finger, MAYBE two through a hole in the alternator bracket..but no more. Basically, I need to get something down between the valve cover, bracket, and EGR stuff to pull the boot..then I can feed a ratchet with a flexible piece and extension through the bracket to get to the plug itself. I don't know whether angled boots would be better...maybe if they pointed upwards.

 

The TPS is on the passenger's side of the throttle body. It is a little black device with a 2 or 3 wire plug on it. It basically is a reostat that tells the computer what position your throttle plate is in. I replaced mine on my 1992 Firebird a few years ago when I got a code. I think it was about 20 to 25 bucks for the TPS, and it only took removing two torx bolts and unhooking the wire clip to get the old one off. I think I would start there and at least you will know that it isn't the problem if it doesn't get better.

 

IIRC I used a large flat blade screwdriver and came in from the front. Am able to gently lever the cover & boot up and off the plug.

To seat the boot need to use something to push it down onto the plug from the top side. Yes, real PITA.

RBob.

 

I looked up the TPS thing in my manual earlier today, and got a price...yeah, it's between $20 and $25 and incredibly easy to replace. I've got $30 in quarters..once I change them in, I'll pick up a new TPS. So, RBob, you're saying you used angled boots facing up and it works for you? Hmm...food for thought.

 

They do have boot-pulling tools; I tried a pliers-style once and messed up the pliers AND the boot- but it was a cheap $5 thing, made of flimsy metal. Let me do a search... yep, here's a picture:



And here's the link to that page, but I bet you can find it in a regular auto parts store- I bet sears even has it! http://www.autopart.com/Tools/file/part154.htm Yep, sears has two, but they're both the pliers style- they're made by name brands so they've gotta be better than the aluminum foil one I have. Go to sears.com and search for "spark plug boot", you'll find one by KD tools and one by Lisle tools (only available online). But sounds like you can't get pliers in that area, though.

 

Hey, what a bitchin' website that is! (autopart.com) Looks like they've got everything! They even a fuel gauge SENDER for our cars (General Motors, Firebird (or Camaro), 1986 (for me)) for $99!!! Beats GM's $300!

Wow, go to their Specials page- the emergency lug nut remover (aka "I lost my wheel lock key") is only $16.95!!! I think I found a new parts site!!

 

Wow...niiiice. Hey Tom, I bought and installed a new TPS today. Took the car around the block. I'm not extremely aggitated right now because I understand that the ECM has to re-learn how to operate the car because I disconnected the battery before I removed the sensor....but it was, pardon the slang, SLOW AS A ****. Idled extremely rough too... I'm gonna have to try her out tomorrow morning and again going home and then to work...I'm keeping my fingers crossed...but resetting the ECM has never made any sort of a negative impact on the car's performance before so I'm not feeling good vibes on this one... How do I measure the output of the new TPS? My assumption is...take two of the multimeter probes and touch them to the first and second connectors on the sensor hookup...but should I have the car started and idling, or just the ignition on for this? And which wire to which connection? I SUCK with electrical stuff but I'd like to make sure the new TPS isn't a dud before I start secondguessing things... I can say this though...my Haynes manual's picture was completely wrong. Showed the TPS with some sort of external pin and lever..there isn't one. There's only a little **** coming out, and the sensor fits over the **** where inside the sensor is a little plastic notch..looks like it can go in one of two sides, depending if you rotate the little notch, but I'm not 100%.

 

I'll have to look in my Haynes, but I'm pretty sure for a 2.8 they've got the location correct. Not sure about your 3.1, which uses the self-adjusting TPS. I'll check tonight. (whispers: get the http://www.helminc.com book! Haynes isn't good for this kind of diagnostic stuff!)

 

Yeah Tom, I've never been very happy with my Haynes...it lacks depth. I take it the picture differences between what I have and what's in the manual is just probably a difference between the regular and self adjusting TPS. I assume the regular had a pin that was pulled by another pin linked to the throttle butterfly, that's what it looks like in the photo...mine only has the small inner piece that fits over the stub linked to the butterfly. I might return the TPS considering I'm not really seeing any difference between the new and old one. Also, last night I was driving home after I had just filled up on gas and the car was being a total b*tch...I had it in Overdrive but it was on really early, at 40 mph..so in OD at 40 mph with the torque converter locked, I got a LOT of drivetrain shimmy/kick...like way more than usual. It didn't feel like engine at all this time...and it wasn't the torque converter simply locking and unlocking. It felt like it was either SLIPPING out of lock and unlock, or the transmission was slipping...either way, I was getting a shimmy and kick. Argh!