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Hi I have a 2002 jeep grand cherokee 4.7 liter V8.  Yesterday the oil pessure gauge started to go to just under 3/4 way up the gauge when I accelerate, when I stop at traffic lights it goes back to middle of gauge and then goes up again when i accelerate away. jeep has 87000 miles on it and had oil change 2 months ago (synthetic oil ) any ideas??

Thanks you in advance  

Hi I have a 2002 jeep grand cherokee 4.7 liter V8.  Yesterday the oil pessure gauge started to go about 3/4 way up the gauge when I accelerate, when I stop at traffic lights it goes back to middle of gauge and then goes up again when i accelerate away. jeep has 87000 miles on it and had oil change 2 months ago (synthetic oil ) any ideas??

Thanks you in advance  

change the oil and filter first.. use a filter that you know is the correct part number for your car


check the ground wires... with a digital volt meter...     20 volt dc scale....    negative battery post to the engine block with the engine running and the head lights and a/c on max cool...     if you get over 0.2 volts you probably have a bad ground connection somewhere... between the motor and battery negative...

change the oil pressure sending unit.,..

the oil pressure sending unit.. .. but cheeper than replacing the oil pump;....

if the sending unit is changed... and the grounds test good... time to think about changing the oil pump.. it is possible that the oil pressure relief valve in the pump its self is sticking...  its rare.. but it does happen...

oil pumps always can pump more than the engine can accept...   they have a spring loaded piston to regulate oil pressure.. this is the part i am talking about.. and they are usually built into the pump...  

This is a common occurrence. yet if the oil level is not within a safe range then you may have an issue with the oil or the gauge. Typically anything above the halfway mark is a good reading.. In other words. if the oil pressure was less then 1/4 of the gauge (moving or standing still) you may have a big issue on your hands..

As with my "late" Wrangler, this was common place to see the oil gauge move forward and back depending on the driving conditions.. So nothing to worry about, just means you oil is moving through out the engine.

However, In some cases.. this could mean that the Oil sender or sending unit maybe getting ready to go bad.. For instance, one winter while driving through the snow, a large chunk of Ice bounced off the wheel well and tapped the oil sending unit.. The reading where off the scape (very similar to your) a simply replacement was necessary and things are back to normal. If one has the tools it can be removed easily and replaced on a sunny afternoon.  

Hi,

You will need to replace the oil pressure sending unit. My 99 Jeep did the same thing last spring. I took mine to a dealership. The cost was $112.95.