Hi all, new to the forum. I recently changed the oil in my '99 TJ I bought a couple months ago for the first time. I put it Mobil 1 10W-30 High Mileage and a Fram filter. Before the change the pressure would always be at 40-60 psi. Since the change it has gradually gone down from right around 40, then 20-40 and today, while driving it went to 0 at idle and barely moves up when on the gas. Oil is full and engine temp is fine and hasn't changed so I assume it may be the gauge or pressure sending unit but I really don't know. Has anyone experienced the same thing?