The past week, oil pressure has been steadily rising, from the r-m in normal originally, now runs at the L at an idle after start up, the edge of the box under a load, when I put it in gear, and is pegged after a few minutes of cruising at highway speeds. After cruising at highway speeds the pressure does not fall until idling for several minutes. Bought a new sending unit, but can't find it on the block, checked the entire drivers side, and all around oil filter, no wires, no sensor. Have been reasearching, apparently it is a on or off switch, that is activated between 4.5 and 7.5 lbs, but that does not make sense, as the guage is rising and falling with the rpm's. Also had a scheduled oil change three or four days after it started rising, used same brand and viscosity, as well as same filter. Pressure should be higher after oil changed, but it still should be lower than it is. Rest of the guage cluster works fine and accurate. Anyone have a piece of information or advice for me? I dont even know where to start to chase wire gremlins if that were the case...