99 F-250 with 6.8 started it today and it idled very high started around 1500 which semed pretty normal the started climbing to above 2000 to 2500 and then tried to kick it down went on up tp around 3000 and I shut it off started it a few times today same thing any suggestions possible throttle position sensor?? let me know if you can help thanks

 

Are you sure you have a Ford and not a Toyota Prius?

Seriously, is the throttle body cleaned?

 

Funny I am a Millwright At Fords Indy Plant wouldnt own a Toyota but yes it is clean and it is very cold here just started this morning it pretty much starts at around 1500 rpms and gradually climbs to upwards of approx. 3000 rpms

 

IAC controls the idle if your throttle body is closed tight.

 

I don't know if the IAC valve could open that wide to make it run at 3k rpm. Wouldn't hurt to check it.

I was thinking that the butterfly in the throttle body was sticking when you tried to knock it down with the accelerator pedal.

 

A few years back I had idle problem and I found a little corrosion where the butterfly closes causing it to hang up. I cleaned it up and have never had a problem after that. Take off the air inlet tube at the throttle body and take a look and see if the butterflies are closing all the way.

Denny

 

PCV valve caused my truck to idle up above normal.