I agree with johnnyNITRO's mechanicregarding the oil pressure. The oil pump is the best lubricated part of the engine, and outside of actually breaking and not working, it should outlast the rest of the engine. Worn bearings are the usual cause of low oil pressure. Some people try to mask the problem by installing a high volume pump. The big pump will keep the pressure up, but the parts are worn out and prone to sudden failure. It also takes more power to run the larger pump.