My oil pressure gauge has been going nuts lately. A lot of the time it sits around 45 and at a dead stop around 30. I can't pinpoint what the conditions are when it starts to go haywire but it seems to be on a longer trip when the car is warmed up.
So basically this is what happens, I'll be driving along, and all of a sudden I'll feel what I can best describe as a pulsing vibration that feels like the car is lurching forward several times in succession. It does this several times and then stops. I don't know if this has anything to do with the gauge or another issue all together but it seems that only after this happens is when the gauge goes crazy.
After this point maybe 20 seconds or so later, the gauge will peg past 60 which is as far as it reads, and the needle shakes like crazy. The weird part is that it will read out normal (45ish) when I'm giving it gas, but as soon as it shifts and goes into lower rpms, or I let off the gas and coast, it will peg again. This seems very strange to me. It also seems to be worse in over drive than regular drive.
The part that worries me the most is the weird pulsing vibration that I feel right before this happens. This makes me think it could be a mechanical thing. When I turn the key to turn the power on without starting the car however, the gauge will move completely by itself and go to about 45 and then to 60 and then back several times without the car even on, which makes me think it's an electrical thing.
Does anyone have any insight into this? It's driving me crazy and I am completely bewildered. Thanks!

 

On your car, you have an Oil Pressure Sending Unit (OPSU) on the driver side block just above the oil filter.

This OPSU has a secondary circuit for the fuel pump, so that in the event that the ECM and the fuel pump relay no longer function correctly, the OPSU will send 12v+ to the fuel pump and make it run so you can limp home.

It sounds to me like, your fuel pump relay is going bad is is bad, and thus the OPSU is kicking on/off the fuel pump, causinthe surging issue.

So, I'd be checking the fuel pump relay, and it's connector, and replace maybe.

I'd also replace that OPSU - it sounds like it's bad anyway - since it's not making a smooth transistion to run the fuel pump and the gauge is going crazy.

It has 3 wires to it, here's a link: http://shop.advanceautoparts.com/web...545538346____#

 

Thanks for the info! I had already bought an OPSU because I figured I would need one either way but the fuel pump relay makes a lot of sense I never would have thought of that. I'll let you know what happens thanks!