I am beyond frustrated with my car. '91 Camaro v6 3.1. I got the car with some front end damage, fixed the body work, and then the problems began. I brought it to a friend and he worked on it at his house originally. The car didnt idle and didnt run right. That is when I learned of this site and I got it running smoother but still stalled. He replaced alot of things for me, as the car had been sitting for 9 years in storage and needed to be tuned up majorly. He changed: the thermostat, TPS, set the timing, check vacuum, new distributor, new plugs, oil change, checked all the basics, and got it running even smoother until it at least idled. Then I sent it over to another friends garage and he got it actually running and inspected. Cleaned the throttle body, and put another new TPS in. New fuel pump and sending unit. The car ran great. Then he did all the dings and dents and painted the car over. The car looks and sounds great. Now about every week, the car acts up and stalls on me in the middle of driving it. Sometimes low RPM's, sometimes high RPM's. It just dies. Sometimes it spits and sputters, other times it just dies completely and I loose power steering etc. I put in aftermarket TPS's in and it was still doing it after running for about a week on the new TPS. Then I got a TPS off of GM thinking that maybe the aftermarket ones were junk. I put that in and it once again ran great! However today, we are back to ground zero. The car stalls every mile or so. Somtimes more sometimes less, its very random. Please help me with some pointers on what you possibly think that it could be before I put a wrench through it. Thanks everyone!

 

First off, the car looks like a million bucks. Very nice job on the paint and body work.

I'll grant you that the problem is somehow electrical in nature. The "lightswitch" behavior between running great and shutting off says only electrical issues can cause that. So forget about bad fuel pumps, leaky injectors, burnt valves or anything mechanical in nature.

The three two most common problems are:

1. Bad grounds. There's quite a few, all need to be properly attached.

2. Bad ignition components. That includes everything inside the distributor as well as the ignition coil.

3. Bad ECM or faulty/shorting wiring between the ECM and various critical sensors.

The TPS has been replaced quite a few times, so that's not it (plus a bad TPS won't shut the engine off, although it's not fun to drive with a bad one). The fact that you have no check engine codes (does the check engine light even work??) would again suggest ignition issues since they rarely throw trouble codes like a bad sensor reading usually does. I'd recommend getting a scan tool and seeing things like the ECM sees them. You really don't know squat until you see it from the computer's point of view. If it doesn't give you any clues then it again points fairly strongly towards ignition stuff.

 

Thanks for the reply. I scanned it a week ago and it said bad TPS and I changed it. Now, it doesnt throw any codes. The light used to come on for 5-10 seconds and then shut off but it stopped doing that. Now that there is a new TPS, there are no codes whatsoever. I'm thinking about getting a new ECM and trying that in the car. There are soooo many things to try. Thanks again.

 

I'm grasping at straws here, but do you notice the odd idling issues after you disconnect the battery?

Apples and oranges here (more like fruit and meat differences) but my '92 Lumina with a 3.1L has to do an "idle learn" anytime after I disconnect the battery. It surges and will die intermittently for a few days and then it'll settle down.

To bypass the irritation of crazy idle for those few days, as soon as I restart after having the battery disconnected, I leave the trans in drive and let it idle in the driveway until the cooling fans cycle on twice. From then on, it's good to go.

 

If it still has the stock Multec injectors in it replace them. What happens is that the coils short out and they stop injecting fuel. South Bay Injectors offers reman Bosch injectors that will work better then the Multecs ever did.

http://www.southbayfuelinjectors.com/

If the trans is an auto the idle relearn that paulo57509 outlined needs to be done. This is required whenever battery power is disconnected from the ECM.

To add {edit in} check the coil wiring in and around the bracket. There is a GM TSB about the wires sometimes chaffing through and causing the ignition to cut out.

RBob.

 

RBOB, thanks for the reply. I will look into the injectors and the coil wiring. Sounds pretty logical. Thanks!

Also, I have my fan hardwired to an accessory wire because it was not coming on but all the relays were good. I was confused and I just hardwired it. How else would get the car to "relearn"?

 

Don't forget the IAC (Idle Air Control) valve. Make sure it and the passage ways it sits in are clean. Could be sticking on occasion.

 

make sure your intake is sealing and get a scantol with the GM-1 connector and activae the only calibration function available: T/B relearn. This will check your TPS. Had to do it on my 2.8 a while ago when I swapped Throttle bodies