Pressure @ 120, Add oil warning light comes on intermittently, but crankcase oil level above max and looks thin.

however, coolant level normal.

Any ideas?

the Pressure sender has gone out. Its very easy to replace.

you have to remove the drivers side Tire, and splash guard and access it thru there. The Sender is above the oil filter

Actually Aim to the oil pressure switch/sender. This is a pretty common issue on the 00+'*. Easiest way to get at it is through the passenger side wheel well. It is located directly behind the Power Steering pump.