A friend of mine has a '00 Ford F250 that will not idle. It starts kinda rough and will run fine as long as you keep your foot on the gas pedal. Let your foot off the pedal and it will putter and die.

I unplugged the MAF and IAC and no change in the symptoms. Also, there is NO codes unless I unplug something. So, no CEL and no stored codes. I unplug the MAF and I immediately get a code. Then I unplugged what I think is the IAC and I got a code.

If anyone has an idea of what's going on, we'd appreciate the help.

 

Compression?

Stage0?

Misfire?

 

Looks like it's the IAC. Still working just plugged up.