ok its a 90 f150 302 5 speed when the engine is warm on my way to work i push in the clutch to shift at 2000 rpm and it revs up too 3000 and slowly drops down or until i shift and put the load back on so going down the road i push in the clutch and it revs up to 3000 from 2000 it only does this some times and for a little while at a time i have swapped the iiac and the map sensor and cleaned the throttle body checked for vacume leaks couldnt find any and i got a code 22 maap sensor and code 12 idle speed out of range and code 33 egr valve not closing properly i checked the they all seem to be fine anything else u guys can think to try im stumped and so are the guys at work i work at a ford dealership as an apprentice any help would be great thnxs

 

that sound like an egr problem

 

remove the throttle linkage to the TB, now manually open it - doe it return to close on its own? (I have a 90 TB with perfectly fine springs that binds in the throttle shaft due to gunk built up where the same thing happened)

 

ill check the egr valve thisafternoon and ill have a look at the throttle body the only thing is the truck only does this sometimes it was fine for the 20 miute drive to work and as soon as i pulled in it started to act up again so i duno but ill try what uve said thxs

 

Mine does something similar but it is a loss of electricity for an instant. I'll step on the clutch or engage the turn signal and blip ... off/on and there go the high revs as though I just started the rig.

 

Measure the TPS output through it's whole range, it's possible the sensor has a dead spot at part throttle. This would explain code 12 you are getting.

 

ok it seems i have the high idle fixed with a new iac but now it just seems to be missing on idle as if one cylender isnt firing i have spark at every plug capr and rotor are brand new wires are less then a year old ive checked all the vacume lines again nothing. what do u guys think?