Hi, Bought a F250 4X4 manual tranny with CA smog equipment. As far as I can tell everything is in place and hooked up. Got it cheap and it runs great but burns lots of fuel. Here's the deal. Starts hard when cold. Usually have to crack the throttle plate to get it started. Runs about 1000 rpm until warm, then the idle jumps to 2000 and stays there.
I unplugged the IAC. It dies like it should. Took the IAC solenoid off and I can make it idle wherever I want by moving pintle with my finger.
If I take the vacuum hose off the MAP it will start fine and idle about 650.
No codes or check engine light. What am I dealing with here?
Any help would be appreciated.
Thanks, Bob

 

So you checked for codes and there were none or because the light isn't on you didn't bother?
Idle problems like this are usually sticking part in the throttle linkage or cable, or a bad TPS but that should throw a code.

 

Just got back to work on the truck. Conanski, you had it exactly right. I said no light, no codes but what I meant was no CEL. I pulled the codes today and sure enough it flashed 13, TPS out of range. Replaced it and off it went. Thank you very much.