jsteph0221

I am new here so please bare with me. About a month ago I took my 1994 f-150 pickup to the shop new get a rebuilt long block , it ran fine before just had a knock in the lower end so I thought it was time for a new motor. The problem now is when it is first cranked it idles high as it should but when it warms up it tries to die . The shop has replaced the MAF , dist , computer and now is trying a new upper and lower intake . please if anyone has an answer please let me know.

snafumonkey79

Sounds like it could be a vaccuum leak, they can be tricky, but the best luck I have with them is to use carb cleaner (3M safe for coated throttle bodies) and spray around all vacuum lines, throttle body and intake to head mating surfaces. If the idle changes or engine dies this is where the problem is. Don't spray intake ducting. Also check coolant temp sensors and possibly IAC.