Originally Posted by Torque454
I cleaned the IAC tonight with carb cleaner and it did not change anything. It was dirty, but its still doing the same thing. It may not be as bad (wont know until i drive it more) but its still doing it.
I think it might possibly be something to do with the throttle position sensor but i dont know. I disconnected the throttle position sensor and drove the truck without it and it acted the same as it did when it was plugged in, with the exception of the fact that it wouldn't idle.
Other symptoms that I think are leading to the TPS are: hesitation at light throttle - cured by giving it more throttle. Jerky at low speeds.
Usally you can unplug the iac motor it should stop the madness. Try to clean the tps up with wd40 some of them can be cleaned. They are cheap and so just replacing it is not a big deal to be sure. Motorcraft ones seem to last the longest but cost the most.
When you cleaned the iac did you clean the throttle plate where it seals up around the body. Also the holes that lead around the throttle is where it gets clogged. Make sure you can see spray coming out the back side when the throttle plate is open and you spray into the holes.
Also it will take a few minutes for it to smooth out. unhooking the battery for an hour should reset the computer and force it to start over from scratch with factory settings. Once it gets confused it will start up in the wrong mode and try to postion it back to the old spot that wasnt working. Best to clear the computer and start it learning over.
When you reinstall the tps try to twist it out of the same postion it was in before. Computer will adjust and some times you can move it around a bad spot. You can test it if you have an ohm meter just connect to the wires and open the throttle and see if the ohm meeter goes flat or jumps aorund when you move on and off idle. Car does not need to be on of course. I think it should be around 5 ohms at idle. But its been a while.
Sorry for the book i have done this so many times just trying to help.