High idle

[50Pilot]

Okay so heres my dilemma. I bought this car last monday, and its got a high idle. And no im not dumb, i know where the adjustment is, i backed the screw out all the way and still idling at 1,000. Now heres the kicker, i plug in the IAB (or IAC), start the car and after a while its at like 1,500! So without that plugged in its fine, but i dont know what the engines doing without that plugged in. And 1,000 is still too high. So can anyone throw me a bone as to what the problem could be? I still dont get why it goes higher with the IAB plugged in

 

[bentley429isBAC]

It sounds like the IAC to me, had the same issue a few years back swapped it out and was good as new.

 

[HISSIN50]

If it idles great without the IAC plugged in, clean the IAC and be prepared to get a new IAC if that doesn't work.

Otherwise, be on the look-out for vacuum leaks.

 

[jrichker]

See the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[50Pilot]

Thanks guys, i hate to sound like a newbie or a dummy but these 5.0 motors are all new to me