I have a weird problem. Sometimes when I start my 1998 Explorer 6 cly 4.0 the motor sounds like there's no oil in it. It'll quiet down after running for a minute. And sometimes when I start it, it is so quiet. It happens on hot and cold days. I just spent two days on the ground installing a new oil pump because I thought possibly the pump may have been draining out. But needless to say 2 days and $ 185 less and I still have the same problem. Anyone else ever experience this problem. The truck only has 108,000 miles