I just got this car a few days ago and I honestly haven't driven it much until tonight. I was doing about 80 so around 3k rpm or so and I glanced at the oil pressure gauge which was reading 0. Uh oh. I pulled off at the next exit, checked the oil (again) and it was fine. The car ran fine and I figured the gauge just didn't work. I got back on the road and as I was getting on the highway the gauge started reading normal (60psi or so at higher revs). As I cruised it fell back down to 0. I accelerated again and it climbed up to about 20psi and stayed there the remainder of the ride (20 mins). On the way home it didnt work at all until I was about halfway home when it started reading around 20psi again. Could this be a wiring problem? Or is this an indicator of a deeper problem? I bought this from a friend who rebuilt the engine himself and says its always done this (and swears its an elec problem), but I don't know. Any help?

Its a stock GSL-SE w/ 13b and runs great as far as I can tell.

 

first, check the wire at the oil pressure sender. make sure it is clean and tight over the sender's stud.

 

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Under the oil filter. If the wire is grounded and the car is turned on, the meter in can be damaged internally.