I've been having this starting problem with my car for a while now. It will catch, then shut off. After 3 or 4 tries, it will stay on, but the idle goes up and down until i rev it and get going. I've already replaced my O2 sensor, MAF sensor, idle coil, idle module, checked for and fixed all vacuum leaks, and even tried replacing my brain box
(CPU?). My computer isn't putting out any trouble codes, everything is running at the right levels, and even my fuel pressure is right where it's supposed to be. Today I took it to the chevy dealer and they checked it out. The guy said it was my throttle position sensor. They charged my $175 to clean it and run all the diagnostics on it, and they changed some gaskets. I asked if it could be the VAT system, but they checked and said no. If this doesn't fix the problem, any ideas of what it can be? Help!! I'm running low on cash and patience.

 

I think the chevy dealer gave you a stroke job. For $175, you should have gotten more than just a cleaning and some gaskets.

How many miles are on the engine? What all mods have been done? Heck, what engine do you have?

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If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Ported Plenum,
SSM SFC,
Boxed LCAs,
8mm Accel wires, Flowmaster Exhaust,
16" GTA rims.

'97 Bonneville SSE

 

i have an L98, about 200k+ miles, all i've done was a cat back and runners, but it did this before mods. i'm planning on more mods, but need more info on what's wrong before i start. if the dealer didn't fix it, i'm going to raise heck, but i really don't think they helped much.

 

Does it hot start ok, or does it experience a no start condition regardless of temperature? If it hot starts ok, I would suspect an IAC adjustment problem, or faulty IAC valve. If the condition is present both hot and cold, then the TPS may cure it. Its difficult to say without seeing an analog sweep of TPS resistance. Bacically, when a TPS goes bad, you may increase resistance in a certain position, which can cause stumbling, and if it fails at or near its position in idle, you may have a no start condition because of it. Let us know what happens when you get it back from the dealer.

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-Jason M. 1991 Camaro Z28
"Its Blue."

 

200+ on the clock, you may have to much slack in the timing chain. There are too many possibilities to start naming specific components, but with that many miles, you need to factor in mechanical wear, on top of air/fuel delivery.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Ported Plenum,
SSM SFC,
Boxed LCAs,
8mm Accel wires, Flowmaster Exhaust,
16" GTA rims.

'97 Bonneville SSE

 

well this is what happened at the dealer, they said it wasn't doing anything wrong and well I took my car and it did it again. Oh the dealer said they wouldn't guarantee the work. So I m screwed out of 200 hundred, I m going to call the shop foremen and have alittle discussion, and if that doesn't work I ll call who I have too to get this resolved. Well any way I checked my vac pressure, and it was at 19 I changed out my IAC with my buddy's I don't know if that did it yet, I ll update you guys after I test it out.

 

well this is what happened at the dealer, they said it wasn't doing anything wrong and well I took my car and it did it again. Oh the dealer said they wouldn't guarantee the work. So I m screwed out of 200 hundred, I m going to call the shop foremen and have alittle discussion, and if that doesn't work I ll call who I have too to get this resolved. Well any way I checked my vac pressure, and it was at 19 I changed out my IAC with my buddy's I don't know if that did it yet, I ll update you guys after I test it out.

 

Ok I just found something else out today, I came home from work and didn't start my car up for about 5 hours and it started to stall out again, I put the pedal to the floor and it wouldn't even catch, so I turned the key all the way back to off and cranked it back on and I got it to almost get it running again, oh I left my foot off the gas this time. Its kinda of weird I need to hit the gas after it catches to keep it from stalling out. Oh by the way I changed out the IAC with one from a buddy of mine it seem to help alittle bit but not much, anyone got any ideas?

 

Dacuma, Have you tried unplugging the MAF and then starting the car? I'd guess it's one of your MAF relays, esp. since you have already replaced the MAF.

 

thanks red devil...which relays are for the MAF? i know there are two, but i don't know which ones they are. i think there are only five or six relays in total, so if you know which ones, it would help me out.

 

Red Devil,
Thanks buddy, I replace my MAF Relay and now it starts like a charm. The problem is fixed now I can get back to modding out my car. Well thanks again, you were right on the money. Fellows I got to tell you the Chevy dealership couldn't even tell me what was wrong, those guys don't have clue. The Thirdgen message board rocks, thanks again guys.