I have a 90 f250 5.8 auto that will try to run but dies. It won't idle at all and to keep it running I have to pat the pedal constantly. When I try to rev the engine it dies. I've got spark, air, and fuel. Good fuel pressure. Can't find any vacuum leaks. Check engine light doesn't come on at...

I have a 90 f250 5.8 auto that will try to run but dies. It won't idle at all and to keep it running I have to pat the pedal constantly. When I try to rev the engine it dies. I've got spark, air, and fuel. Fuel pressure is good. Can't find any vacuum leaks. Check engine light doesn't come on at...