I have a 1986 dodge ram D150 with the 3.7L L6 engine and I have had a couple problems leading up to the one i'm posting about. I replaced the exhaust manifold and gasket because the original one had deteriorated so badly that moisture got to the gasket surface and pitted it, but I replaced all that and the truck was fine for two weeks and now it will start cold and run until the engine warms up and the choke turns off. I have checked for vacuum leaks and there doesn't appear to be any so the truck has been sitting in the driveway because i'm at the point where I can't think of what else to check. Has anyone had this problem?

 

Could it be a problem with the power heat valve in the exhaust instead of the carb?

 

Well I replaced the exhaust manifold be since it was cracked then I fond out that the gaskets in Pretty much everything were shot so I rebuilt the carb and put a new gasket and manifold so what else could be wrong with the power heat valve?

 

Power heat valves can hang up. I concentrated on the exhaust because that is what you said you worked on. You didn't tell us you rebuilt the carb. Are you sure you adjusted the mixture screws correctly? Is the warm idle set correctly?

 

I have a 1986 dodge d250 with almost the same problem,it was running fine but now it wont idle out of nowhere,does anyone know what that could be?