I second the idle air control valve, aka idle air motor / idle air control / idle air control motor / and so on... They are a real pain in the butt as they all seem to gunk up over time, Ford isn't the only one, bmw's have them too... And erratic / high idle is exactly how they act, actually...
On bmw's when they go bad the result is usually a constant surging engine, in a stick shift it sounds like you're trying to race.
And it doesn't go away when shutting the engine off, but perhaps on Fords that resets it?
Once you know what a faulty idle air valve behaves you'll almost always right away know this problem but if you don't know what it's like the only way to troubleshoot this might be to replace it with one that's known to be working.
If it's not that it's either a vacuum leak, worth checking all those rubber hoses first.
And if you're in the mood you can get into the EGR but that's usually behind the air filter way in back up under the firewall.
If you have a vacuum gauge it's easy to diagnose for leaks.
On a side note I can agree that EGR is a load of BS.
Last edited by herler; 11-17-2012 at 07:01 PM.