My 1992 Bonneville SSE, once warm, drops to 10psi Oil pressure! Idle is about 550-600. If Idle were a little higher I'd be fine but Damn computer settings!! Pressure fine when driving and fine if idle were 750-800. Mechanic confirmed 10psi. Any tricks for higher Idle? Suggestions? No knocking or anything. Tried heavier oil. 81000 miles. Wonder if mechanic messed up and all I need is sending unit. How replace?? I'll try it.