My 1998.5 Dodge Cummins has been dying for sometime now. It starts cutting out then shuts off. While it is cutting out, the oil pressure bounces around. Sounds like it runs out of fuel so I thought it was the lift pump going out, so i bought a raptor 150. Continued to die. Then i thought maybe i was flooding it with the 150gph so i bought and installed a stock lift pump. I just replaced my VP44 pump last summer. My chips are off. Just a stock truck dying. Any Ideas...???