jpfoster

So when I go to stop or am stopped, my idle drops very low, bounces and sometimes dies. I have changed the IAC and the MAF. I have not reset the PCM though. I haven't really noticed anything with the hoses, but I haven't really inspected thoroughly. Any ideas?

Bert

What year, engine, etc. Autozone will pull codes for free. Don't reset it before you go.

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Bert

Jeff Collision

The problem you are describing in most cases is a bad IAC (idle air control) valve and or a dirty throttle plate and throttle body. Since you changed the IAC valve, the problem could be with throttle plate. You can clean it with a good brand of carb cleaner. If cleaning doesn't work, then run this test on the IAC. Check Idle Air Control (IAC) solenoid function - backprobe the WT/LB wire of the Idle Air Control (IAC) solenoid with a jumper wire. With the engine idling, momentarily ground the other end of the jumper and the idle should flair high. Inspect the throttle bore for gum and varnish deposits. Hope this helps.

CatSkinner

Depending on year, make, and model, you'll have some variations, but the following link will take you trough throttle maintenance. Make sure you've taken care of any vacuum leaks, first.
Ford Mustang IAC IAB - Solving your idle problems

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