CivilizedApe

I am having oil pressure problems with my 98 XJ, 2d, 4cy, 167,000 miles, compression 150 across all cylinders. I bought the truck with a oil pressure idiot light on. Since purchasing it I have replaced the oil pressure sending unit, crank and rod bearings, oil pump rebuilt by me, oil/filter, oil pump new, mechanical oil gauge, non Fram oil filter, non idiot light gauge cluster, and thermostat. I have good pressure 45 at start up but by the time the truck is at temp at idle oil pressure is down around 0-10. Under acceleration it gets up to about 20 when hot. I am pulling my hair out with this issue. When I replaced the rod bearings they were worn into the copper but the crank bearings looked good but got replaced anyway. The one thing I didn't do was use plasti gauge to measure the clearances. I just used the same bearing size that came out. I am searching for a 4WD manual XJ for a swap but I wanted this to run in the mean time.Thoughts on places to go from here? F it and run it till it pops?