i'm still working on the 91 f-150 with the 5.8. finally got it driveable thanks to the fuelpump but now when i first start it up the idleing goes way up past 3 grand then comes back down to around 1 grand.i can unhook the iac and the idle does change so what else can i check?

 

change the iac and or the tps

 

already took iac out and cleaned it and changed tps sensor back when i was having other troubles

 

Suppose it's possible that the IAC has failed or is still sticking?

 

alright guys and gals i just went and pulled codes and it kinda looks like a lottery ticket theres so many of them.but if someone can translate for me i thank you in advance.here they are,33-34-41-51-67-99

 

Here's one of many sources available - need to scroll down a couple of pages' worth - http://www.troublecodes.net/Ford/

Looks like you've got some fun coming!

 

33- EGR valve opening not detected.
34- PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
41-HEGO sensor circuit indicates system lean (right side).
51- ECT sensor signal is greater than the Self-Test maximum of 4.6 volts.
67-Neutral safety circuit failure.
99-Electronic pressure control circuit failure (E4OD).
or
EEC system hasn't learned to control idle.

Did you disconnect better to reset anything? if so you may have to wait till the eec learns to control idle

 

would any of those cause it to idle all crazy and feel like there is no power when you drive it.like when you go up a hill and wonder if your gonna make it.also it sounds stopped up on pass.side exhaust,cant really describe it,but i know it sounds weird.

 

was your engine up to temp when you searched for codes?

 

it was still warm.parked for maybe 15 or 20 min.