All,
Had my oil changed about 500 miles ago (not that it may matter), but for the first time I've owned the car (now has 90K on it) I received a "Check Gauges" notification and "Low Oil Pressure" note. Looked at the oil gauge and it was sitting on 0 pressure. I reved it up to see if it would move, it did (a little) and then I shut off the car. Checked oil, is full, no leaks, no funny noises before hand, etc. Started the car, and the gauge was reading normal. Drove about 15 miles and got the same message again. Went to pull over and about the time I was to put it in park, the gauge popped back up to normal position. Went another mile, and the same message and oil gauge 0 pressure was back. Pulled over, shut it off, checked everything again, started it, pressure gauge reading good again, and drove it home. Started it this morning, no issues, drove it 22 miles and still no issues. The day before, pulling into my driveway to get the mail, put car in park, and noticed that the idle RPM was fluctuating up and down. Got in, reved it up, and it stopped. Thinking I have an electrical issue somewhere? Pressure sensing unit? Gad gauge? Replaced GXP instrument cluster with a rebuilt one about a year ago (due to faulty tach) while under warranty. Hope I don't have to do it again on my dime! Scared to drive it with not really knowing for sure what my problem might be. Don't want to melt the engine, but it sure seems like an electrical connection, pressure switch, or gauge issue. Any Suggestions??
Thanks in advance-
Gary

It sounds like it could be a bad oil pressure sensor, or a bad connection at it.

Have the oil pressure checked with a mechanical oil pressure test gauge, to rule out any internal engine problems. Factory gauges aren't the most accurate to rely on.

Haven't looked for it, or done any research yet, so does anyone quickly know where the oil sending unit/sensor is located on this engine? I've not had to crawl around under this car much, so I'm not real familiar with it'* layout under there! I'm tempted to put a new sending unit/sensor on it, (while I'm under there) IF it'* easy to get too and remove.

On the 4.6L it'* on the oil filter adapter:

WOW! I was going to be happy with verbal assitance. I appreciate the picture! Now I know what to look for!
Thanks-
Gary

You're welcome! Be careful when installing the new sender, torque spec is 16 N·m (12 lb ft). You don't want to break the new sender or worse, crack the oil filter adapter. Good Luck!

My oil gauge did the same thing!!! And stayed at 0 for about 3-4 days and then it went back to working for 2 months before it did the same thing!!! My Fuel gauge decided to go bad and when the GM dealership checked the gauges with their computer (making all gauges do the sweep with a command from the hand held PC) they replaced the dash gauge under warranty.. So that fixed the oil gauge issue!! But good luck fixing urs..