I have an 85 with a 12a. For some reason at idle the oil pressure shows to be around 40 psi but once driven or revved at all, the oil pressure gauge maxes out at 110psi. I also noticed that engine vibration feels a little different. I'm suspicious that it's not getting oil.

Has anyone had this problem or can you point me in the right direction (or thread)? If so how'd you fix it? Any recommendations?

 

do you have a performance oil pressure regualtor in your engine? has it been shimmed? i woud check the wiring for a break that can cause a short. you may also want to remove the pressure gauge and temporarily install an oil pressure gauge in its spot to see actual oil pressure. this will ensure your gauge is reading correctly.

 

The factory oil pressure guage is not very accurate, especially after 20+ years.
Installing an aftermarket mechanical OP guage is the only way to *really* know what's going on.