xplod_69

i have a 94 z28 camaro with about 187xxx miles on it. when the engine is warm it starts to rev up on its own when im at a complete stop. when i have it in neutral it dosn't do it as much. i've already changed out the fuel filter and checked the fuel presure and everything was fine, i also changed out the PCM, and its still doing it. i also changed out all spark plugs and wires. i was wondering if anyone had any clue what might be the problem. thanks alot.

Robbie Boyd

used to happen to me a lot. look into getting a new optispark.

welcome btw.

xplod_69

but if i change out the optispark do i need to change out the timming chain too.

lt11997

It would be a good idea if it has 187,000 miles on it.

_SHIFT

Before you get into your opti can all of the vacume lines for vacume leakes, my pcv valve line that went from the valve cover to the TB had a leak and it caused my car to idle higher like you described.

xplod_69

how do i check for vacum leaks. and where do i start????

_SHIFT

just check all of the hoses, and all of the lines that are hooked into the intake manifold. I had to replace my pcv hose, and my air pump hose also got a hole burned into it (thanks shorty headers ) and that one caused an echaust leak. check the IAT and the intake elbow for any holes or tears that could be causing any potential problems as well..... i hope some of that helps ya

xplod_69

well i checked my hoses, and the pcv hose was cracked. i went down to auto zone but they told me that i can only get it thoguth the dealership. how much does it cost and how long might it take to get it. hopefulyl this fixes my problem>

The95Firehawk#250man

hey there sir, when i got my motor rebuilt it did the same thing upon fire up at the machine shop and it cost me like 100, 45 part i think and labor it was my idle air control valve thats what mine needed

smoknta

With that many miles, you might just need to clean your IAC valve.
IAC = Idle Air Control
It is what the PCM uses to control the rpm at idle. It might be sticking on ya. It is mounted under the throttle body.

xplod_69

i do i clean it out though, and also how would i know if i would have to replace it. i hope thats the problem casu ei already took it to a mech and they charged me 800 and didnt do a damn thing exept change out my PCM...thanks for the help though

_SHIFT

i work at an auto place so i get it at a discounted rate.... i think it was like 12 bucks or somthin.....but diffinatly replace is if its cracked like mine was (when it cant stay on the TB...just slipped off)

smoknta

You need to put it on a scanner to see if the IAC is working. Or use an IAC test tool that the dealership has.