so got this 1990 302 2 wheeel drive f150 rules a** at towing and high speed travel but i slowly but surely started replacing everything but i cant figure why when i start it ,idle is around 1200 then goes to 800 i got some add ons but nothing helps ,vaccum lines are fine what else could make idle and jump rpms like crazy i just need a base plan fellas i had it since i was 17 its got 240,000 on her and i hope to make it last

 

Sounds like a problem with the IAC. Some have cleaned it with good results.