So lately the oil pressure on my '99 cherokee classic has been rising and even hitting 80 psi while COASTING down hills. I know that the oil pressure is known to fluctuate with the rpm's, but this is strange. Not accelerating or on the gas at all, it will rise while going down a hill then come back to normal at a stop.

The oil pressure otherwise is steady at 40 and rises on acceleration, then comes back to 40.
It is worth noting that it has just recently started getting chilly in the mornings here in WV.

Took it to the shop because it also hesitates sometimes on acceleration, and they said they couldn't get it to act up at all. What's your thoughts?

 

My gauge also does that on my 99...had a compression test done everything's fine...most likely a plug and play deal i would start with a new oil pressure gauge and see if that fixes your problem! Let me know how it goes!

 

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Being as this is an intermittent problem, I would just go ahead and install a new oil pressure sender and report back.

 

I would go ahead and replace the sender, but the shop had said the pressure reading they were getting from their equipment was the same as what was coming from the dash. But then again, it apparently didn't act up for them.