My engine idles fast sometimes (1100 to 1300 a lot of the time). It really concerns ms when I let off to come to a stop. After a few seconds it will settle down and stay at 600 or so. I leave it idling a lot in the summer to keep it cool on the inside.
98 4.3 185K
I think he just means when it's cold; not like for weeks or something.
Also the IAC stands for Idle Air Control (Or something like that) It's a valve that regulates the amount of air getting into the engine when your foot isn't on the gas. if it gets stuck, then the computer can't regulate the idle anymore, so it can stall or idle high.
1991 4.3 TBI Blazer 4x4, 5 speed
painted DIY intake & Junkyard E-fan
Mark I -Complete
Mark II - planning phase
It is weird.
During the day just driving around in traffic, it will not idle down when I stop in traffic.
It will stay around 1500 till I get it stopped, then it will fall to 600.
It does it at 60 or 80 degrees.
Where is the IAC on the engine if I need to replace it?