[legion]

I just got into Florida an hour ago. My truck is having some "issues".

I have a '97 F150 with the 4.2L V6. As I was climbing some hills in Tennessee, the oil pressure would start to waver (this has never happened before). This would happen every time I climbed a long hill. The problem would go away when I filled up with gas.

As I pulled into the hotel in Georgia last night (parking uphill), the oil pressure dropped completely and the warning light came in. I started it up this morning, and it was fine the whole trip, until I was low on gas and climbing one of the causeways to get out to Merritt Island. When I got onto the island, the oil pressure would start to waver when I came to a stop light. The problem went away when I filled up on gas.

I replaced the oil pressure sensor last year (I had the problem once a year ago, replaced the sensor and it went away...until now). There are no oil leaks. I changed the oil in the truck the night before leaving for Florida.

Could I pretty much assume the problem is the oil pump?

Any ideas what one is going to cost to replace?