41 Ford rough running, backfiring, and hard engine vibration

[cadillac512]

Quote: "Engine is vibrating like crazy at idle, and when I first start the car cold, I often only run on four cylinders. I have the idle backed all the way off, and shes still running high."


This REALLY sounds like a vacuum leak...and a fairly large one at that. Look at all the intake manifold vacuum ports,the intake manifold gasket (even if you have to remove the intake) and maybe spray carb cleaner around the sealing surfaces of the intake and carb with the engine idling. You'll hear the leak and the engine will smooth out if you find one.



Terry