2004 Jeep Grand Cherokee 4.0 oil pressure bounces down and up multiple times at a red light.

JeepNWilly

JeepNWilly

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Been a while since I posted something. My son recently got a 2004 Jeep Grand Cherokee Laredo 4x4 with a 4.0. Engine runs smooth and quiet. When starting the oil pressure goes up to normal quickly and stays up there. While driving pressure is good and when we stop at a traffic light the pressure guage starts bouncing around. Up down back up back down to almost 0 then back up past center and back down. Once we get moving it stays with normal pressure.
 
JeepNWilly said:
Been a while since I posted something. My son recently got a 2004 Jeep Grand Cherokee Laredo 4x4 with a 4.0. Engine runs smooth and quiet. When starting the oil pressure goes up to normal quickly and stays up there. While driving pressure is good and when we stop at a traffic light the pressure guage starts bouncing around. Up down back up back down to almost 0 then back up past center and back down. Once we get moving it stays with normal pressure.
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I’d start with removing the sensor/sender and hook up a mechanical gauge and check under the same circumstances. If all is good, probably just a bad sensor/sender. If not, you might need a new oil pump.
 
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macleanflood said:
My TJ did that until I freed up enough slack on the wiring harness and got it better secured. That and a Mopar oil pressure sensor.

-Mac
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I figured since engine runs smooth and quiet shouldn't have oil issue. Wonder if I can still find Mopar pressure sensor. I am plan on changing it any ways.
I read somewhere that the 2004 GC oil pressure guage is not a true pressure guage. Kinda like a dumb light. Not sure how accurate is that. If that is the case then it is strange for the needle to move up down at different ranges when I am at a traffic light
 
Correct and all the more reason to plug in a mechanical gauge and check.

I bought one on Amazon for something like $40 and you can "rent" then from most auto parts stores. They'll all have 1/8" npt.

-Mac
 
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