What is causing the oil gauge to stay at 80 psi. How do I diagnose the underlying problem. 305 /700r4(brand new). Has always run a little fast in the idle, but Rpms settle after putting in gear. .

 

you have to determine if the fault is with the gauge or lubrication system. You should put a mechanical oil pressure gauge on the engine to measure the oil pressure. if the master gauge reads normal...the fault is with the sender, sender wiring or pcm. if the master gauge matches the trucks reading...the fault can be oil pump or a restriction in the system.

 

Does pressure drop at all as motor hits operating temperature?
Does it lower at idle vs 2000 rpm?
Is it at 80 or pegged all the way right?