i have a 90 f150 5.0L i just put plugs cap,rotors and wires while driving the truck runs smooth but it wont stay idle in park or drive. the check engine light is off. could it be the TPS? or could it be something elese ? thanx Darrin

 

Could be either the TPS or IPS.... Idle position sensor..they are both located on your throttle body and can be removed and cleaned with Cab cleaner or replaced if needed. Mine did the same thing ...I ended up replaceing them both after cleaning did not solve the problem. I think both were 80-90 bucks.

 

Does it have an IAC (idle air control) sensor? It would be on the TB as well... You might clean all your electrical plugs around there with electrical contact cleaner as well... Clean your TB with TB Cleaner and a toothbrush and wipe clean to avoid dislodging gunk into the engine.

 

Fixed !!!!! it was the TPS i had to take off the throttle body. the hardest part was the screws that held the sensor on. I striped the philips head on the screw, so i had to use vise grips then i made it so that i could use a flat head screwdriver. thank god for Drimals.