Hardly

This is an odd problem. I have a 1994 camaro V6, auto. What it is doing is puzzling me. Only on occasion does the problem happen.
When is does happen the follow occurs: While cranking the engine it will not fire up if the gas pedal is not touched slightly, after it does crank (but again, only if I step on the pedal) once I let off the gas pedal it immediately dies, it does not burp, grunt, run rough or misfire or anything, it just dies as if I turned the key off at the very moment I let off the gas pedal. The car runs fine if I keep the rpms up but again, the minute I let completely off the pedal the engine dies. Now, the next day it might crank up absolutely fine, idle as normal and run great. It might not have this happen for weeks, then one day it will do it again and die immediately after letting of the pedal.
When the car is not having this problem, it runs fine, cranks fine, cranks without ever having to touch the pedal, idles fine and drives fine. I have no idea what it could be.
Any help would be appreciated.
I have recently replaced the following when I did my last major service, both oxygen sensors, both crank sensors, a new MAP sensor, new plugs, new wires, fuel filter, air filter, idle control valve, belt and a new gas lid. The car has 117,000 miles.

Feenix

Recheck your idle control valve. That or a serious vacuum leak are about the only 2 things that would cause that. And since its intermittent, I'd be aiming my sights on the idle control.

Hardly

I'll put in another idle control valve and see how it does.
One more thing to add, in driving it today, it has been having a small burp at idle at stop signs and stop lights, sitting at idle the engine on occasion has a small burp or "second of death" in its running, but as you take off above idle the car runs out well.
I need to figure it out so I can correct the problem once and for all.

Need4Camaro

Your fuel pump could also be going south...

Feenix

Typically when its a fuel pump its the opposite. Once you touch the gas pedal is when the fuel pump will show weakness where it may be fine at idle. Less demand while idling, and once you give it a bit of pedal it'll hesitate usually.

Hardly

o.k. here is todays update. I checked all vacuum lines and everything is tip top. When I turn the key on and wait, I can hear the pump buzzing for a few seconds and then quit. As I tried to start the car today it did it first thing. Here's the rub, if I keep just the ever slightest amount of pedal the car will stay runing at 1000rpm, if I let off that tiny bit it dies immediately, not burp, not hesitation, no rough idle, just as if I turned the key off. If I double foot it, one on brake, one on the gas as I drive I can keep the rpm above 900 and drive the car, once I get on the road all is fine as wine. then, after I drive for say 5 or 6 miles the problem is gone and it idles as normal and as I drove home today all was fine, went to Ace Hardware, turned car off, came back, hit the starter, not touching the pedal, car fired right up, idled fine, I drove home. One thing it does do, and I'm sure it is related to whatever is causing my problem is that at idle it will on occasion have a stumble or hesitation in its otherwise smooth idle.
So, I hear the buzz from the pump if I turn the key on but not start the car, so that works. Once I do follow thru and start the car it may or may not have this problem. When it does have the problem it dies immediately if you let completely off the pedal but will not fire up at all if you don't give it some gas and has a burp or stumble every so often at stop lights and such at idle. Otherwise runs out well and drives at all speeds perfect, no roughness, no sluggishness.
Any other ideas on what to check or look at? I don't want to throw a bunch of parts at the car blindly hoping to hit the one thing that is causing it, I'd like to find out exactly what is causing it so any help is appreciated.

Hardly

the last 2 days all has been fine but it will do this again soon. Still has a "stumble" every now and then at idle. I'm sure this is related to the main problem if we can pin point it.

bobbyk3lly

my guess is that you need to change your air ilde control valve and maybe a tunes up, that should solve the stumble and the starting issue.

bobby

Hardly

Already had a tune up, new air filter, oil/filter, spark plugs, the usual. Still has the stumble. I would probably bet that the random "dying" actual culprit is the very same reason for the stumble, they started happening at the same time. But again I don't want to just throw hundreds of dollars of parts on it, I want to narrow down the possibilities until I find the actual culprit and to know in the future what caused it. Any "tests" you guys can give me to perform that eliminates "certain thats" from the list will be helpful.

TGGodfrey

When it does it you can ohm out the coils in the IAC to rule out an IAC. Do the same with the TPS. If the TPS has shorted you can have the same problem. The ECU might be going into Flood clear mode thinking the plates are 100% open.

A Scanner connected would show you the TPS values as well and you want to make sure the TPS is showing around 0%.

Hardly

thanks TG, I'll be prepared to do your list and check back.