My 92 Cherokee, with 240K miles, was getting a reading of 80+ psi for oil pressure. I checked quantity and was a quart low so I added a quart and pressure is now erratic (goes from 40 to 80 for no apparent reason). Now it gets weirder. I changed the valve cover gasket and replaced the broken vacuum line from the crankcase ventilation elbow on the valve cover to the manifold. So now I have erratic oil pressure and the car hesitates on acceleration and during regular driving plus the check engine light comes on intermittently. I'm at a loss. Any ideas??? By the way, NOTHING else was removed or replaced or disconnected or broken...

 

The check engine light tells u there's a trouble code(s). Have the code(s) scanned/read. That's a good place to start. That's usually where a shop will start.....scanning for codes. The oil pressure reading is probably a faulty/bad oil pressure sending unit/bad electrical connection, etc.

 

Two completely different problems. Oil pressure is the sending unit. When they read extra high like 80 psi the connection near the filter on the sending unit is full of oil/dirty or the sending unit has failed.