Not sure if this is the correct place to post this, so i apologize now if it is not.

Back before my car's transmission went out, i was running into a problem where at a stop or a red light, my firebird would start idling up and down real badly until it would eventually die unless i continued to give it gas. I already replaced all the vacuum hoses i could get to so im wondering if this could be a case of a "going out" idle air control valve? I read the symptoms of a bad or going out one and it seems the bad idle at a stop or red light is the exact case. This doesn't get very bad at all until the car has heated up.

So if i should go ahead and replace the idle air control valve, which specific one do i get? Cause i noticed some expensive "FI - fuel injection? idle air control valve" Do i just need this one?

 

I had a similar problem with my 5.0 Liter 84 Z28. Stumped me to point of pulling my hair out. MAF sensor TOTALLY fixed the problem. Make sure that your Vacuum hose is attached to the MAF sensor. Mine wasn't.

 

It's MAP on the '90 v6 and it's possible the iac passages just need cleaning. Take apart and start with that. And make sure there are no vacuum leads of course. If that doesn't do it there are things to check/try.

 

Ok! Thanks, ill take the iac out and check/clean it. If its perfectly unclogged or clean, then it may just be a bad one. Could it also be the MAP ?

 

It's not just the iac that needs to be cleaned it's the passages in the throttle body. Take it off open it up make sure it's clean. Especially where the pintle on the iac sits. Be careful with the iac it's a little delicate. There are several things to check. Some things can be tested on the car or bench tested. Do you have a manual?

 

Ok good tips, i will be gentle with it and completely clean it all up as well as the passages. I have a automatic.

 

Ok so today while i was pushing on my IAC valve, i noticed the engine lowerd in RPM when i pressed in on it. So after taking it out, i replaced the rubber O ring. Seems it had a warped O ring so it was sucking in some air all the time. After replacing the O ring on that its running better, however still kinda idle'd odd. So i had my friend adjust the timing on it since it seems i may have had the timing a bit off all this time. Its running alot more smooth and better now, and even starts better with the timing changed, however its running rich smelling now and he's gonna adjust the timing some more tomorrow to get it just right.

The EGR is missing a bolt on 1 side so its probably throwing out exhaust air from there since its all black on the metal around it. However i don't think this would cause the idle problem, i think this would just give me less gas mileage and the smell of exhaust, which i have yet to ever smell any exhaust from the engine.

I havent checked the MAP yet and will do so tomorrow.

So i guess what im getting at now is, is there a guide on correctly setting the timing on this car without a timing light? Or must i just do what we can tomorrow then when i go to get it smogged, have them check the timing first?

 

Set the timing to spec. I'd need to get the manual out to be sure but I think it's 10 degrees before tdc. There's a procedure to follow so you should get at least a Chilton's manual.

 

i do have the 1990 firebird manual book, ill go ahead and check there. Thanks.