I've just replaced the pump with a new one, and the pressure is still bad. The light comes on from 72 to 90. When it's cold, up to 70, everything is fine. The low- and high-side valves are closed, open, and high-side valves close under acceleration. Later, at 72, the low-side valve even opens, and the oil pressure warning light starts popping up. I don't know what to do anymore. I'll replace the oil filter base. Then, if that doesn't help, I'll start disassembling the top of the engine. Any suggestions? I'll soon have to buy a second engine so I don't have to bother troubleshooting?