I have a 90 F150 with the 302. For some reason the idle shoots up to about 2000-2500 rpm. I can tap the throttle a couple times and it will drop back down. I'm not sure if it's the throttle position sensor or something to do with the EFI computer. It has cruise control that didn't work when I got the pickup but after changing fuses it started working which makes me think it's the TPS.
Any ideas?

 

Could be any number of things. Try to pull codes to see if the PCM has logged/reported problems.

Post back with your codes.

 

Do the simple test with the TPS; put a volt meter across the green wire and either the black or brown wire, and with the key on (engine off), slowly open the throttle and watch the voltage change, It should be smooth and continuous, whether it's from high to low or low to high. You can stick paper clips through the rubber seal on the back side of the connector, along side the holes that each wire goes through. Or you can disconnect the TPS from the harness, and use an ohm meter to do the same thing. In any case, an analog meter works best to look at smooth changes.

 

I ran a diagnostic on it about 2 weeks ago and nothing popped up and this issue has been occurring for several years.