So recently my '93 F150 5speed 5.0 4x4 started idling high out of the blue.
Normal for the truck is around 1100 and it was idling around 2200.
Suddenly one day it started slowly incresing until it was screaming at a stop light at 3000. I heard the belt slipping and pulled over to check it out. I thought maybe the tensioner pulley was locking up so I drove to just 3 miles away from town and it threw a belt.

Long story short the smog pump froze up. There was rubber goo everywhere.

I replaced the pump and threw in a new O2 sensor while I was at it.

It still idles high! I scanned it with a Auto X Ray Code Scout 2500 and it turned these codes.

KOEO
31
33
34

KOER
12
44
33
13

I pulled the EGR out and cleaned it and it didn't change anything.
Anybody have any ideas? I really need to get to the bottom of this!
Thanks!

 

If it isn't sticky linkage, it's usually caused by the TPS or the IAC.

If your EGR was stuck open and the EGR exaust tube was broken that would also alow clean air past the throttle plates, but that's kind of a far fetched scenerio.

I would try cleaning the IAC first thing.