Help with idle !!!!
Senior Member
Joined: Jul 2008
Posts: 58,557
Likes: 1,165
From: Long Beach Calimexifornia
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?
The EGR is most likely stuck open. You might also have a bad engine coolant temperature sensor if you're sure the truck was warm when you did the test. A bad ECT will make it run like crap.