My Bros 1989 f150 6-cyl has had problems since he got it running after sitting for a few years. The fuel system has been cleaned out (tanks and lines). Fuel pressure is good. Distributor is new. New plugs/wires. It stalls when it sits at idle when the engine is warm. Runs rough if it restarts then finally dies. But when it is driven on the highway at highway speeds, it runs fine. Only when he comes to a stop and sits does this happen, as if it doesn't get enough cooling to a faulty sensor. Restarts fine after cooling down. He has taken his truck to three different mechs. They have all charged him several hundred dollars without any fix. No codes. Inspection for leaks around the intake have been check by previous mechs and a new egr valve has been changed. New hoses and lines have been replaced. The passages for the egr valve have been inspected and cleaned as well (as claimed). Any Ideas?

 

Has anybody gone looking for a vacume leak? Maybe ge a good look at all vacume lines, pods and fittings. Could try spraying carb cleaner along intake manifold gasket area. If it has a leak the carb cleaner will stall the engine out...

Bob

 

Has anybody looked for a vacume leak? I'd check all lines, pods and cannisters. Maybe spray carburator cleaner along the gasket area of the intake manifold. If you have a vacume leak the carb cleaner will pull the motor down (try to kill it)...
Bob

 

Has anybody looked for a vacume leak?

 

Thanks UB for replying. I hope spending several hundred dollars that he did have the vacuum lines checked out. If not, I will have a beef with his mechs. My brother was a prior diesel mech but isn't updated with electronics. If it were a vacuum leak, I'm sure he would have found it or at least, looked for it. I'll give him a call and ask him for more detail and post it.

 

Sounds like the IAC valve is bad, especially since it's an idling problem.
Clean that out or replace.