Cant Get Idle Low Enough

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

Mustang5L5 said:

Unplug the IAC completely. Then unscrew the idle stop screw to drop idle down.

Then, unplug the battery for 30 mins. Plug the IAC back in. Hook battery up, start engine.

Let idle 2 min no accessories. Then 2 min with everything you can possibly put on turned on.

Click to expand...

If this doesn't work, start looking for a vacuum leak. I had a cap on a vacuum line under the upper intake manifold deteriorate to the point that it was worthless. Look at it with the upper intake manifold in place and you couldn't tell that there was anything wrong with it