I was going to take my 97 TJ for a weekend trip, and got just outside of town when I noticed my oil pressure which is normally at 40 on the highway was down to maybe 30, then I noticed it drop a little and then go back up to 35. I pressed the clutch in and the pressure dropped to 5+....not good> I slowed down to 65 (from 75 or so) and drove her the 40 miles home at 65. The pressure would vary from 25 to 40.

I installed new standard rod & main bearing and a high volume oil pump 2 years and 30,000 miles ago, and the pressure has been rock stady, and never below 25 at idle after a long highway run.

If it was an oil pressure sensor would it fluctuate and go way low at idle?
If it was the oil pressure releif valve stuck or sticking, it would drop and stay down, wouldn't it?
If it were bearing failing, it would drop and stay down.

any ideas?

Doug Crall

The sensor seems to give a lot of problems...from the posts on this site! Get a new one and try again. Pressure at speed should be more or les constant. Either low or high. But constant. Fluctuating without noises should be the reading units and not the pressure itself.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

I've had some relieves stick on high volume pumps. Because they have the volume, you can still have pressure at idle, just not as much as normal. I'd try the new sender first (if it's cheap), if it doesn't help then I'd drop the pan and check out the pump. It might be something blocking the pickup.