I own a 90 F150 Eddie Bauer 302 AOD 4X4. IT started idling erratically. Over a period of a month the idle started favoring the high side of erratic. Now the idle is at 1200 rpm all the time. I've cleaned the Idle Air Control Valve. No change. The resistance at the IAC Valve is 11 ohms. The voltage with "KOEO" at the IAC Valve is 11 volts. With the engine on, the voltage is 13.8. I"ve tried disconnecting the IAC Valve while the engine is running and there is not a change. Also, I only receive trouble codes after disconnecting the IAC Valve. The truck runs great, other than the idle. Could this be a computer problem? The computer does directly supply voltage to the IAC Valve. I'm hoping someone could compare readings with mine. If anyone has any ideas, I would greatly appreciate hearing them and the help.
Gerald

 

I've got the same issue on my '90 F-150 w/ a 302. I was running at around 1500 @ idle and replaced my IAC and the TPS. Unfortunatly nothing changed, I'm prolly goin to take my IAC back sense it doesn't seem like the issue. And I'd love to come across a sensor to read my TPS.

So I'll be anxiously awaiting any possible fix's......

 

check for vacume leak the 302 was known to have intake gasket leaks betweem the upper plenumb and the lower intake. You can take some carberator cleaner or use a propane torch unlit and go around the differant areas and see if the idle changes, also check the pcv valve and hose and block off the vacume lines to eliminate other sources of leaks, but the most common problem and easy to change is the gasket.

 

+1

 

Hey thanx chucks and faster! I'm not to familiar w/ 302's yet, and I'll deffinatly be checking that out through the week.

Thanx again for the tip!!!

 

Well, looks like you guys were on to something.

I just wanted to offer my thanx, this forum is better then any other source I've ever come across.

Thanx again guys