Oil pressure light on

[quote:559002eba1="MGNTWO"]I have a 95 eclipse gs non turbo with a bit of miles, 145,000. The engine locked up and i did a rebuild with new bearings, crank, piston, rings and valves and replaced oil pressure switch. When at idel when the car and oil warms up i lose oil pressure bad, then if i rev it it regains pressure but i have to keep the rpms higher as the engine heats up. Any idea whats causing this? My first guess is oil pump but a mechanic told me he doesnt think its that.[/quote:559002eba1]
I would certainly think it was the oil pump did you check this when you did your rebuild, If not remove the oil sender and fit a oil pressue guage and get the pressure reading other causes worn out sender unit or oil pressure relase stuck hope this helps