I drive a 1996 Mustang v6 3.8. Back in July I took it to a mechanic for what I concluded was bad bearings, once he started working on it the oil pressure completely cut out. I've since had a different engine (only 40000 miles) put in from a 2001. I had some vibration in the engine since it was put in, and when I took it in Friday to have that resolved, the oil pressure cut out again once the mechanic started checking things out. I've already put in a new oil pump, and if it gets primed pressure gets restored, but the mechanic isn't sure if that'll be consistent or if it'll drop out again. Need an expert answer. Between the engine replacement and Friday I've had oil pressure every time, which makes this extremely frustrating. Thanx for the help.