I'm suddenly having an engine idle problem with my 1990 GTA (5L/auto). I read a post on here already related to the IAC valve possibly needing cleaning, for low idle problems. That's one thing I'll probably check.

I've noticed the low idle problem during the coldest parts of the day only (so far). Its usually 30F or below in the morning/evening. When I start the car, I allow a complete fuel pump prime (sometimes 2). The engine starts but idles extremely low and ends up stalling. Sometimes I'll restart and it starts up with no idle problem at all. Or if its idling low I've given it some gas and eventually it starts idling ok, but this takes some time.

Does anyone have any idea if this sounds like a bad/dirty IAC valve? Id think the idle would be low all the time if that were true. For my case, once the engine is warmed up, the idle is fine (500 rpm or so).

Thanks

 

Could possible be the IAC, but I had a similar problem and it turned out to be my injectors. Nothing wrong with cleaning the IAC first though. You might want to do a search on here for IAC cleaning. I don't remember exactly but I think you kinda need to be careful how you clean it.

 

I read not to use carb cleaner on that post you're talking about. Also, I think wd40 could be used to clean the IAC.

I have a hunch you're right on about the injectors. They are old and have been worked on before by a not so capable shop. They indicated that some were not triggering and supposedly the shop replaced the bad ones. I'm sure I could use a brand new set. Which do you recommend that work with the factory computer?

Thanks

 

Check with injectors plus. They are a sponsor on this site and quite often post very helpful responses. I haven't heard anything bad about them. I got my injectors from Summit Racing but I knew what I needed and Summit was the only supplier that stocked them. I don't know how mechanical you are, but injectors aren't hard to replace. Time consuming, yes. Just to be on the safe side, take pics of how everthing goes together before you get started. Makes it easier to figure out when you start putting it back together. Also, I believe there is a how-to video on you tube. Don't get in a hurry and you'll do fine.

Steve