Hello all, I'm new here. I just got an 87 T/A WS6 305 TPI auto with 49,500 miles all stock with a hole in the muffer and mid pipe LOL. The car runs kinda good LOL!, it was not driven much as you can tell. Ok heres the issue. I do know about automotive as I am a fleet manager for a living went to tech school, but have not wrenched in a long time. Heres what it does. It starts nice cold or hot, idels fine, free rev's fine for the most part, bit of a stumble sometimes if you hit it off idle, but revs free. When cold the car makes good power, even barkes the tires into second at half throttle. Then it seems after awhile of running it starts a funny thing. It ides great, lowend is great with maybe a stumble or two at take off, but when you go to get on it and it hits about 3000 RPM it like hangs there, the trans is not sliping and there is no bucking or missfires, it just kinda dies off a bit or holds about 3K then snaps out of it and the top end power is fine. Whats the deal. I'm gong to do plugs, wires, cap/rotor, fuel and air filters soon as well as new exhaust, but I'm not sure any of them are the casue of the issue?

Any ideas??? Thanks in advance.

 

Sounds like you're getting the usual suspects, but you should also check the pcv valve, and maybe change to a higher octane fuel to see if that straightens it out.

 

1st thing to check, fuel pressure.
With it running 36-42psi.
Key on engine off 42-47psi.
It should hold pressure too, not drop off quickly.

 

These are excellent suggestions for your symptoms. A few other things I would be suspicious of, if none of these things fix the problem, would be the MAF sensor. it's pretty much the big dog of the fuel management system, as it tells the ECM how much air the engine is taking in. If it's off just a little, the ECM will be lost and no code will set for even a fairly large error.

The best way to test the MAF is with a scan tool. But you can check some things out visually. Look for any leaks in the tube between the MAF and throttle body. Get a can of Mass Air Flow Sensor Cleaner and use it to spray clean the MAF. Do not touch the sensor wire(inside the sensor itself) with anything but the spray. It's very easy to destroy.

If you have access to an OBDI scan tool with GM software and the 12 pin DLC adapter, use it to read MAF voltage. Around 1- 1.3 volts is normal at warm idle. The MAF should reach 4.5 at wide open throttle. If it won't go over 3.5 volts, this will cause your symptoms. You can also test the MAF signal voltage with a DVOM on pin B. If the voltage is low, check for battery voltage at pin A and ground at pin C.

 

Thanks guys, this weekend i'm going to start working on it as I have time, I drove the car again last night for a few mins and it ran good for the most part, it runs like a beast when cold, it's once it warms up and runs for a bit, but it does not always do it. I had about an hour drive home when I got it and it was good the most of the way, then when I stoped at buddy's house and
it sat for about 15 mins, it acted up on the way to where I keep it. Also if your doing say 35-40 and stomp on it it will kick down good and go, it seems to do the hang thing when you take off form a stop and get on it to wind it out.

One more thing is the car does not seem to like OD under 60mph, this is the first of many vehicles I have had that acts like that-it likes drive alot better-is this normal? When it does the hang thing the trans will not shift as well till the hang thing is over-any idea's on that. Do I have a TV/cable issue?

 

Check your cable to be sure. You're sure the trans isn't slipping?

 

Yeah, the trans shift great, the fluid is nice and clean looking and smells fine. It chirps the tires into second when the car is kinda cold and still hit hard all the time. Is there a way to adjust the TV cable? Yeah when it does the hang thing the tach does not go up at all, in fact it seems to drop a bit even if you push the gas harder. A shop I talked to on the phone said the CAT might be cloged and when it gets hot it restricts the exhaaust, but if I free rev the car it revs fine and does not hang plus the temp gauge stays nice and cool. The car runs good others that this issue. it starts good, idles good and does not stall ever. Every now that then there is a slight stumble when you got to pull out from a stop or if you stomp the gas to free rev.

 

A clogged cat is a definite possibility. You can test for this with a pressure transducer on a lab scope or just remove the O2 sensor and try a a hot acceleration to look for a change. Still, I think the problem is your MAF sensor.

 

So just get some MAF spay cleaner and spay the wire in the MAF with it on the car then? Does Autozone or advanced sell it? If the CAT was cloged it seems the temp would run higher right?. I'm thinking of gutting the cat or deleteing it as there is a hole on it or right after it, hard to tell-have not got all the way under it-the muffler has a big hole as well so I have exhaust work to do. Like I said i'm going to do a tune up as well, but don't think that will get rid of the issue.

 

The pins you are talking about are on the MAF conector or the data port?

 

At the MAF sensor. Various terminals of the data port can be used for valuable tests but not to directly test MAF voltage. I generally suggest that anyone seriously interested in diagnosing and repairing their own third gen F-body invest in both a DVOM (10M ohm per volt min), and a bi directional scan tool. Bidirectional refers to the tools ability to command test functions of the engine management system. Any bidirectional scanner will also read data. Avoid "code readers" they are a rip off since you can read flash codes with a paper clip.

These cars are old now and the tools that work well on them are also old and can be purchased used for cheap. My personal favorite for any OBDI vehicle is the Snap On MT2500, or Brick" as it's often known. These tools went obsolete (discontinued) about 10 years ago and can be had for around $250 on craigslist. There were so many of these tools made and they are so virtually indestructible that they will be around for a long time. Cables and adapters are still available new from Snap On. The cartriges you'll want to be sure you get with the machine and test it before you buy it.

I recently purchased the new Snap On Solus Ultra, Snap On's newest "keyless" scan tool. It is pretty much the best generic(all makes and models) hand held you can buy. I still keep the Brick I bought 12 years ago in my bottom drawer. Its just so handy on the older stuff.

 

Good bit of info on testing the cat. I don't think it's the cat though, because he said he has a stumble on acceleration and a flat spot in the upper rpm range that it eventually kicks out of and the power is back on. When my cat went, it glowed red hot and made the car lack power everywhere right up to the point it stalled.

 

This is a good point. The engine wouldn't pull out of a clogged cat. The MAF cleaner is made by CRC(silver can labeled MAF Sensor Cleaner") and should be available at any parts store. The tune up may help quite a bit. If the spark is falling off under hard acceleration, that would explain your issue and I have seen this many times. The wires are the most common cause of this. The MAF sensor will certainly cause the loss of power at 3,000rpm. However, I suppose I wouldn't expect the engine to recover from this, unless the MAF was just dirty or had an intermittent failure.

One quick test of the MAF is simply to unplug it with the key off, start the engine and run it under the conditions where the failure is occurring. If the problem isn't there with the MAF unplugged, the MAF is the likely culprit.

 

Yeah AutoZone has the MAF cleaner, and not to sound dumb, but where is the plug for the MAF, this car is not set up like any of the Fords I have had and worked on, I seen the MAF is down kinda low between the air box and that res box or whatever it is. The MAF has a funny clamp on it and did not see how it comes off-can i just spay it from inside the air box?. I don't keep the car at my house so I was only at the place I keep it for a few mins last night. I don't think it's the cat, I know what a clogged cat is like and thats not the issue here. Like I said when the car is cold it runs like a champ with no issues for the first 15-20 mins or so then, well you know. I mean some times it goes good and sometimes not so good. I just need to get time to do the tune up and clean the MAF. Like I said it comes and goes, but seems to happen every time I drive the car. Also is the PCV hard to get to? I bought a Hayns manual, but it's not all the helpful on half the stuff I have looked up.

List of things i'm going to buy-tell me if they are good parts

MSD cap & Rotor Part 8406.
AC Delco Plugs, Copper.
K&N Drop in air filter.
Taylor Street Thunder plug wires
WIX Fuel Filter or from Autozone
PCV from Autozone
Clean the MAF.
Gut or get a MagnaFlow cat.
Get some sort of better flowing and sounding exhaust. My stock system is Holy.
fix headlights, replace the bushings. Still need to figure out how to get to the bottom headlight assy bolts since my headlihgts will not come up at all.

 

I forget you have a TA. Your MAF is in the air intake duct just about half way between the throttle body and the filter can. BTW, the TA really benefits from a good cold air intake setup. The stock air intake is even more restrictive than the Z car's To clean it, you will have to remove it from the tube. Some year models had one time clamps that have to be cut to remove. You should be able to replace the clamp with a large hose clamp.

Your parts list looks very good. I run the MSD 8.8 wires myself, but the Taylors are fine.

 

Yeah the MAF has to have one of thoes permanet clamps as there is no screws on it, are you sure a normal hose clamp will hold it back on? I don't want to get into a mess. I will look into a cold air intake as well as i hate the looks of the stock set up. If I can get to the MAF to spay it will it hust it to do it on the car? I love this car and always wanted one, but starting to wish I would have a less complicated car for a toy/project LOL!

 

Update to my cars problem. Over the weekend I cleaned the MAF, put a K&N drop in, in new PCV and hose, new fuel fitler, removed the rusted exhaust and cat, the cat was all broken inside and clogged. Well after we did the fuel fitler, PCV and cleaned the MAF and had the cat back off, the car was running worse, stumbling alot and at times would not even really run, Noticed the cat was all broken inside. So yesterday I cut the cat off, since it was rusted on, started the car with just Y-pipe and it seemed to run good, I had to push it into the garage on Saturday night it was so bad. So for the time being I put a 2 /1/2 24" summit glasspack woth a foot long dump in it's place of the cat and it seemed to run good, got her back on the ground, let her warm up and was heading to dinner, the car kick hard down the long driveway then when i pulled out on the street, it stumbled so bad I had to turn right around and take it back to the garage it harly ran. The car is going to a good shop tonight to get the plugs, wires, cap/rotor put on and some diag done. This car so far is the car form hell. also the air pump is still on and the belt is tunring, but there is no air coming out of the air tube as i just have it open right now under the car, that might have been why the cat failed?

 

Have you checked the tps for possible sticking? Make sure the shop does and injector balance test, and see if they won't check the purge canister for you too.

 

No i did not, ran out of time so it's going to the shop. I just don't have time right now and I want it running. I will have them look into that stuff.

 

ok there's a lot of posts to sort threw so im just going to look back at the original problem.

you say the car has a slight hesitation off idle with a flat spot in the mid range the clears out and you get full power all the way up. definitely sounds like a fuel issue.
normally id point right to the injectors, evean new the spray pattern on those old factory multecs are about the same as a garden hose, but seeing as you problem seem to just vanish as you get moving there not to blame in this case, if they were it would do it all the time. and like someone already said, the MAF is the pretty much the heart of the fuel injection system, telling the PCM how much fuel to add. being that you're problem was intermittent and has developed into a constant annoyance its a sure sign that an electrical component is slowly fizzing out, again pointing to the MAF.

i hope you have good luck at the shop you brought it to, and i would love to hear what there diagnoses is.

 

Well I drove the car to the shop last night, It started right up so i droped it in gear and went as it seems to get worse as it warms up, it ran kinda ok down the long driveway and to the stop light, but I got stuck as this very long red light, it idled fine, ran kinda ok up the road about 1000 feet and then it started looping and would only go about 20mph no matter how hard I pushed her then after it did that for aobut 1/4 mile then back fired my buddy that was following me said it shot about a foot long flame out the pipe then ran a bit better, but still not near up to par, just got it to the shop, then it idled fine at the shop. The problme got way way worse after we cleaned the MAF, changed the PCV and hose and fuel filter. I don't know man, hope it's nothing too pricy as I spent more on this car then I was going to on a project car.

 

Be interesting to see what they come back with. The loss of power and back fire makes me think of what ASE said about the cat...

 

Bit of an update. The shop called me a bit ago and when they hooked the OBD I scanner to my car there was no data conection. The shop has a ECM from a v6 Firebird so they just put the PROM chip from that ECM into mine just to see if there was a connections and there was. The shop was having a hard time finding a PROM chip so I called Summit and the only one they had in stock is the Motorvation stage I PROM. I just had my parents go pick it up and they are dropping it off at the shop as I type this. So do you guys think besides needing a tune up-it's getting that while it's there as well the car will be fine or is this the tip of the ice burg?

 

These cars are getting older and will always need some kind of work. We can stay ahead of alot of it with regular and thorough maintenance. One thing that of course really helps is to do a complete mechanical and electrical restoration. This is pretty much what I did, along with some substantial upgrades to the chassis, suspension, powertrain, steering and brakes. Now pretty much every part of my car is new and installed or built by me. The upgrades bring up to par all the areas that were lacking on it originally. I can be sure now that everything is in excellent condition.

 

Well Summit did not have any chip that would work so now the search is on for a stock PROM chip and then hope for the best. I have a feeling that when I sprayed the MAF it might have screwed it up. The car started running really bad after the MAF was cleaed, K&N installed, PCV and hose and fuel fitler. The fuel PSI is great, K&N is not going to do it nor the PCV so the MAF might be screwd up, but for sure the PROM is bad so that is the starting point. The tune up is done and no change in running. I have to say I think i'm going to get her running good, clean her up real good and sell her-just hope I don't take a loss. I mean the car is very nice, but not worth it to me at this point. Always wanted one and now not so much LOL!

 

Don't be discouraged. You purchased a 25 year old vehicle. Chances are that much of the wiring and connectors are original. Buying older cars are not for the faint of heart nor light of wallet. When I bought my 89 project 3rd gen, if it had a connector, and I needed to touch it, i replaced it.

There are too many posts on this forum of people who buy these old vehicles and get frustrated because they did not go into it with their eyes open understanding they bought an old car. You'll get through it but little things will creep up from time to time just because of the age.

 

I have had older cars before, A 1990 Stang GT, 87 Monte Carlo, 81 Regal, 78 Chevy 4x4, 72 Nova just last summer and a ton of other more normal vehicles and bikes. I guess I just had better luck with the others out of the gate so i'm a bit pissed at this car. I might keep her-might not, not sure I care at this point, but one thning is for sure I can at least ad it to the long list of car, trucks and bikes I have ownd.

In the mean time it has to get running no matter what. I talked to my shop and they found a few used PCM's with PROMs that will work for my car so my fingers are crossed at this point. I still have a feeling the MAF night have got messed up when I cleand it with that CRC MAF spray, but have to hav the PROM in first.

 

then you understand. Not only do we deal with age but also what prior owners did or did not do. Camaros tend to be vehicles that at some point were owned by a cash strapped kid and they show it. For not much more money you can get a vette and they tend to be better maintained by their owners.

I know that if I pull the connector to the MAF on my 4th gen it goes into open loop. it runs rich but still runs. I can't imagine the 3rd gens are different. The ECU tends to be the last thing I suspect.

 

Well I am only the third owner of the car. First owners were adults, The last owner was a 70 year old man that drove it a few miles to the store and stuff and did not do anything to it in 3 1/2 years besides a new ALT and tires. I have some cleaning to do when I get her back. The MAF connetor is a pain to get to on my car-have to remove the air intake ducting and on this car it sucks. So far this car is the hardest to work on. makes the Mustangs I had a 1995 and 1990 seem like a go cart to work on LOL! Yeah I have read on here and talked to some good techs and they say the PROMs don't go bad to offten, but from what the shop says it sure does seem like it is the PROM or that is at least half the issue. I woke up today with a better feeling and I feel we are a few steps alway from a good runing car. Unless there are some messed up wires, I feel it's the PORM, PROM and PCM and or MAF and the car will be fine. fuel PSI is great, it just had a full tune up, engine has super low miles on it and the ING systems is fine.

 

I am an ASE Master technician L1 advanced engine performance specialist by trade and a drivability and diagnostic specialist. I say that not to boast but to point out that I use the CRC MAF cleaner alot. In fact since I first heard of it, I have used it on no less than 100 MAF sensors. I have never had it damage a MAF. I suppose using it on a sensor that is powered up wouldn't be so good but when I suggest cleaning the MAF I assume that you will remove it from the car, clean it, then let it dry before reinstalling it.

 

I might have messed up as I left the sensor pluged in, but the key was not even in the car, I did take the intake ducting apart, but did not want to cut the MAF bands that hold it to the ducting so I just spayed it like that and let it dry well before starting. I used the straw that came with the cleaer and held the can back about 3-4" away from the MAF screen, did that on both sides a few times.

Who knows at this point? Do you think the EGR is messing up as I know have a very free flowing exhaust?

 

A free flowing exhaust applies less pressure to the EGR valve. It could be sticking open due to carbon build up. You can check by applying vacuum and looking for the engine to drop off or stall. The MAF sensor may have been on it's way out and cleaning it may have just been the last straw. You may also have a poor connection somewhere in the circuit. You may want to look carefully at the MAF connector for pushed out pins or a spread terminal. Since it is hard to access, be careful of bent male connector pins on the sensor itself. When wrestling with difficult connectors it's too easy to bend these delicate pins. They can be straightened if your careful. Proper MAF operation is easy to verify using a scan tool or a volt meter. As torque is good suggested, connector failure is common on these older cars. Unfortunately repair connectors are getting hard to find but Standard Motor Products still offers many.

 

well right now my PCM will not talk to the scan tool at all, shop thinks it's the PROM as they have another PCM there and hooked to it and they got readings, but when they installed my PCM it went dead. So have to get the PROM or whateer it is working and go from there, All I know is the car is not drivable really.

 

The ECMs do fail. Not as often as most people think but they do fail. It sounds obvious that yours has. Once the ECM is in and working, verifying the MAF sensor will be easy.

 

The shop is saying the PROM chip is bad and the ECM may be good, I think they have a used PCM and PROM on the way. Man I hope that is all it is, I want the car back so bad, I have not even got to wash it yet LOL! i want to drive i and enjoy it till I figuar out what I want to do with it.

 

Ok this car keeps getting better LOL! So the shop called me a bit ago and they got the used PCM and PROM in, car ran real good then started falling on it's face. They hooked up the fuel PSI gauge to it and the pump is bad. They also said the fuel is nasty and the tank needs to be drained and cleaned out. So far all other reading are good now that the car will talk to the scan tool. Shop is hopeing to have it done today, if not Monday. I want to get her back and clean her up, awesome weather this weekend and I'm going to put her up for sale to see if I can get my money back or as much as i can. Think i just need to stick to my Harley for fun.

 

My IROC gave me a few hard knocks when I first got it. The after a year of owning it, I put it in the shop and spent 4 months rebuilding and modifying it into my dream car. 13 years later, I wouldn't trade it for any other vehicle on the planet.

 

Well after more cash right off the bat then I had planed the car is back and running great! It runs and drives like a new car for the time being LOL! I say that as i'm sure something else will go wrong sometime . The MAF is fine, I now have 2 PCM's for the car and less money in my bank account. I spent Saturday morning cleaning and rubbing the car out and got it about as good as i can for hand runbbing, but she looks good for 25 year old abused paint. The car was not drove in the winter and garage kept, but not washed often, but is an awesome looking 20 footer

 

Glad to hear you got the issues fixed! I am in the same boat with my 86 T/A with only 47,000 miles. I am going straight for replacing my fuel tank. Your post has helped me out, too.

 

Yeah low mileage cars are cool, but that means not much has been replaced so you get to, plus all that sitting is hell on the cars. I now have alot of cash in a short time wrpped up in the car, but it's a 100% rust free 3 owner car. I even have some service invoices from the 80's as well as the window sticker. Yeah keep your head up and bank account open and you will get her going.

 

Yeah, talk about 20 footers. Mechanically, my Beasty is nearly perfect. Cosmetically, she has had a few bumps and scrapes. Nothing major just little nicks and dings mostly. She still looks very nice when she's shined up but I wait for the day when I can take her in for a thorough body clean up and new paint. There are some cars on this forum that look so perfect. I want that for my Beasty.

 

My car just has little dings and some deep scraches here and there, inside it's about 90% perfect. My spoiler is cracked in a few spotes, but never gonig to replace it unless the whole car is getting painted and that is a long ways off. As long as i can keep her running and driveing good I will be happy as she is such a nice car to take on on nice days.