So I noticed a couple of weeks back while I was cruising on the road that my oil pressure reading was zero, I said HOLY #*%* and instantly shut the car off, I had no idea how long it was at zero for but It was odd since I didn't hear any odd noises from the engine, I started it back up and it's my normal oil pressure again. For context my gauge likes to jump all over the place sometimes but most of the time it gives a steady reading of 30 at idle, 40 cruising, and 60 WOT if it's not having a spasm, sometimes the gauge just pegs itself backwards and I need to bang on the dash to reset the gauge, anyways I was testing the TV cable setting in my 700r4 and went to go WOT so it could downshift, which it did, I look over and I see zero for the second time, I just shut the car off and coast to the side, restart and my engines oil pressure is normal again. Not knowing what to trust I go ahead and buy a mechanical gauge from autozone and plug it into the port above the oil filter and route it all the way through the car to the dash, once I did that I started the car and was dumbstruck when I see two totally different readings, My mechanical gauge says around 22-25 at hot idle while my stock gauge says 40??? wtf? my stock gauge is plugged into the port right next to the distributor which to my understanding is AFTER the filter so how is it magically gaining pressure?.. At crusing my mechanical gauge says 45 psi and my stock gauge reads 60... Idk what to believe at this point, all I want to know is if that drop to zero actually meant anything or if it's just an 80s gauge being shitty, and in the future which gauge should I use?

 

The sending unit could be bad or the gauge could be bad. I'd replace the sending unit first and see what happens...

 

"Testing the TV cable" = you are VERY CLOSE TO the oil pressure sending unit and its wire

Check all that over VERY CAREFULLY. You now ALREADY KNOW where, physically, the problem is located. Like, is it plugged on securely; is the connector tight (sqwwuueeeeezzze it a bit with needlenose or something to assure); is the wire broken where it meets the connector; is the tab on the OPSU loose; SIMPLE stuff like that.

 

Since "percussive maintenance" appears to correct the gauge, it's pretty obvious that your primary failure is the gauge itself (You'd have to bang the dash pretty farkin hard to get the wire on the sending unit to reseat / reconnect itself)

And, if your thinking of keeping the mechanical gauge, which given the "quality" (or lack thereof) of the stock gauges in these cars, really ain't a bad idea, I have one piece of advice here that you REALLY oughta heed;

The plastic piece of crap that comes with aftermarket gauges is a sure way to end up soaking your car's interior with oil when it breaks, as they ALL eventually do. Spend a few bucks and get the copper tubing kit and install that instead.

For the princely sum of around $15 you can keep your carpet from smellin like the Exxon Valdez, do a proper job of installing this and it'll last for the life of your car......