What are some reasons my car wont hold idle? It starts right up, but as soon as I let off the gas it stalls. It'll do this for a few days then be OK for a few then back again.

I took it to a service station and they cleaned the injectors, TB, and EGR and put in a new fuel filter. Apparently there was a lot of carbon build up. This seemed to help for a week or so, then it started again.

The TPS and IAC are fairly new. Could it be the O2 sensor? Or maybe a fuel pump or regulator problem?

I'm afraid to start throwing money at it and not be fixing the problem.

thanks

 

i have almost the exact same problem of mine dying on startup. it even died after it had been running for over 10 min while i was scraping ice off it

im convinced it's a fuel problem (filter or pump) but a buddy that knows a million times more than i do says he thinks it's the coil......i do not envy you a fuel pump replacement, and i hope for both of us it's the coil

 

I had the exact same problem before my car went down. I replaced the fuel pump but that didn't help either. So now with the car down I am doing an overall on the stuff so the problem will be gone with the new engine.

 

then maybe the coil? what a relief that would be. if you end up trying that before i do and it works let us know!

your egr just recycles the gas vapors, i dont think it affects idle. the o2 sensor tells the computer the mix of gas/air to use, it would have to be really F***ed up to cause this, if at all.

i wouldnt be surprised if my friend turned out to be right and it is something in the ignition. it wouldnt be the first time he proved me wrong.

 

Mine dies as soon as I let my foot of the gas. If I hold my foot there for like 10 minutes then drive it for like 15 minutes, it will hold an idle. But then a few days later same crap all over again.

Unfortunately, I rerplaced the coil when I installed the Accel 300+ ignition, so I doubt its that.

 

Do you seriously have to KEEP your foot on the gas for long periods of time upon startup, not just some revvs? That can't be good for the engine, especially in cold weather.

From what I understand, a car needs spark, fuel, and compression to start. So if your ignition is all new, you might wanna think fuel pump. That's not to say you should go pay someone $300 to drop your gas tank till someone else smarter than me says the same thing.

 

I dont rev it. I just hold it at 800 rpm, so I'm really not hurting anything.

I'm thinking fuel pump or regulator too. I'm just not sure if the symptoms are accurate for that.

 

I don't think it is the coil or it would cut out even if you were holding your foot on the gas. Coils usually show signs of weakness when the car is warm. I think that it might be your throttle position sensor on the throttle body. Check it out.

 

i have had similar problems, i took the heads off had them rebuilt, put everything back together and had it tuned. then that night when i was driving it, it just started shuting off when at idle, i thought i ran out of gas which i kinda did, my gas was sitting for 3 weeks i burned all the old gas and filled it up with new gas and it did it a lil bit but now its fine, but then it did it again started bogging when i was driving with fresh fuel... so i am sure its fuel, then when i had the AC compressor on it killed my engine, then after a few hours everything works so check your pump fuses, fuel lines and injectors, there are so many dam things that come into play with the TBI and TPI set ups. it can be one thing like injector pulse time that leads to other problems, if you cant find a direct source of fuel cut off just talk to a mechanic or a camaro specialist. i have heard of this problem alot.

 

Have you done a throttle body change in your mods ? If so maybe the IAC motor isn't actually plumb'd correctly. Early model had a direct hole through the plentum. Your 90 doesn't..

 

Yeah I noticed a slight stumbling at part throttle too. Its gotta be a fuel thing. I wish there was a way I could narrow it down before I take it to the mechanic. A regulator is 60 bucks, injectors 200, and a pump with labor is probably 350. I could do the first two by myself but not the last. I just dont want to buy the stuff, put it in, and then find out I still need a new pump.

My throttle body is original.

 

Then for $30 you can get a pressure tester and check the system instead of just replacing components by guess.

 

True. I've just never used one before, and I need someone to hold idle for me.

Thirty bucks sounds cheap. The gauges I've seen are going for 60-80.

 

You really don't even need the engine running to test pressure, just the fuel pump.

As for the test gauge, you can look around for one of these: http://www.actron.com/cgi-bin/web_st...d=7308654_1326

And if you think you have an injection problem, check out the Garage Sale:

http://www.actron.com/cgi-bin/web_st...d=7308654_1326

 

wow.. thanks!