After checking my vacuum pump's ESOF fault (as posted all over the internet) I realized the problem was my PVH solenoid. I figured I'd save a few bucks by buying the DORMAN version. Bad idea. After installation; The vacuum pump turned on frequently (every few minutes) even when the ESOF was off. Finding out that the device is leaking; Instead I bought a Ford part. Either that or wait for the pump to fail prematurely. In any case. The Ford part solved the problem. ESOF works and the pump does not need to be turned on often. Thanks to Revain's return policy; DORMAN is back where it should be - on the shelf, not in my truck.