I have a '91 F-150 with the 302ci V8. The engine runs alright when cold (more or less), but as the engine warms up, the idle RPMs get really high. With the transmission in park, it'll idle up around 3000 RPM. When I disconnect the idle air bypass valve connection, the idle drops to near normal.

I checked the voltage to the bypass valve and it was right at 11 volts, and the resistance of the valve itself was right in the normal range (11 ohms). Does the fact that unhooking the connection drops the RPMs to normal indicate that I need a new bypass air valve? Someone said it might also be the MAP sensor (?). Thanks for your help.

-Sam

 

You might want to remove and clean the valve. It might just be sticking.