Ford Aerostar XL
Ford Expedition XLT
Why would Oil pressure in 1997 Aerostar be fine if it is not shut off but if its shut off and then restarted pressure only goes up a quarter of the way and builds up slowly till it's back to normal?
If you hold the engine at high rpm, dose the gauge go up? or
dose it go up then back down? The oil pressure should reflect the
engine speed. If this doesnt happen, replace the oil sending unit.
Probably only $20 - $30.