i have a 1990 f150 5.8 when it idols down after start it will idol down and amost die then up it will do this a few min then die anybody have any idea why

 

May try to clean the IAC valve located on the throttle body. Unplug the sensor connector. Remove the 2 screws attaching it, careful not to damage the gasket if possible. Clean well with brake cleaner or electronic cleaner and be sure to keep the solenoid part dry and free from any chemical.

 

Welcome to the forums.

Yup, I'd check into the IAC first. If they get cruddy, they will get sticky and not work smoothly. Thus your idle will surge.

 

Billy IDOL is not a problem

idle on the other hand

 

thanks guys i think that fixed the problem