So I've been having power issues with my truck. Taking nearly 40 seconds to hit 60 MPH going down hill and losing speed while going up hill. Started at bottom of hill at 50MPH and ended at 45MPH with WOT at the top of the hill. I had a friend of mine hook a computer up to it and he said my Oil pressure is running at 800psi with a full load on the truck. It should be at about 2000-2600psi while under a load correct? My buddy said it has to be the injector O-rings or the O-rings on the oil rails under the valve covers. Also it is a possibility of an IPR sensor? Is there anyway to figure out if it is an O-ring or IPR sensor? Or does anyone have another idea? I just don't want to rip this thing apart and find out that wasn't the problem. Please Help!!!