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Discussion Starter · #1 ·
Today I was driving mostly in 5th for about an hour and a half. When driving I noticed that my gauge would sit around halfway when in gear and driving. As I would push the clutch in and slow down to stop the gauge would drop to about 1/4 but would rise right back up once back in gear. Did this and watched it a few times and this happened consistently. Is this normal? Should I be concerned? Any ideas/input?

I have a 99 wrangler I-6 4.0L Thanks!
 

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My does this all the time, to my knowledge it perfectly normal
 

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My 1998 does this also, with 83 K miles. The gauge is reading resistance off an oil sending unit. It may/may not be close to actual. Not like it is a pressure gauge hooked up direct to the engine oil PSI. I am supprized about 15 psi at idle-but that is correct. Goes up quickly from there with a little RPM.
 

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Normal. The oil pressure gauge is mechanical in the earlier models of the TJ. Later years they used a electronic system that "averaged" the pressure.
 

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All TJ oil pressure gauges are electronic, the earlier TJ gauges showed the true oil pressure while later gauges were reprogrammed to only show a mid-scale reading unless there is a problem.

Your oil pump is engine driven so oil pressure varies up & down in direct step with engine RPMs... whether the gauge shows it or not. No less than 10 psi per 1000 engine RPMs is a pretty typical/average oil pressure for most engines. :)
 

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To dredge up again - I've got the same symptoms (oil pressure gauge goes to zero when vehicle is at a standstill). It seems unrelated to engine RPM, I can't find any leaking oil, the oil pump seems to be working (getting flow to head when I check it idling). Any reason to suspect it's something other than the sending unit for the gauge?
 
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