My 89 Cherokee oil pressure goes up super high and then returns to normal constantly. It seems to be the highest at lower RPM's. When i am cruising around 25mph (3rd gear?) The oil pressure gage goes as high as it possibly can. When i pick up speed or it shifts and and the rpms go up the oil pressure goes back to normal. When its in 4wheel it does fine, only seems to be an issue when I am cruising at lower speeds. Any thoughts or suggestions on what to check?

 

Im no expert Im sure they'll be along shortly. It could be your Oil pressure sending unit going bad or completely failing. Also dumb question but there is oil in it haha always have to check.

 

The first culprit to consider is the oil pressure sender. Best way to check is with a mechanical gauge. That will tell you if you are getting accurate readings on your dash gauge. If the readings are accurate, then you've got some other issues, but start with the easy to check, simplest things first. If you don't have a mechanical gauge, you could always pick up a cheap version from Harbor Freight, or even do the
free rental from most of the auto parts chains.