i have a 96 ssei. while out last night in Gander i stopped at a red light and the oil gage went down into the red, when the light turned green and i drove off the oil gage went back up to half, which is were it normally sits, it happened only about 2 or 3 time at a stop and then stopped and went back to normal. i bought the car about 4 months ago in Ontario and drove it to Newfoundland with no problems, but i did notice from the time i bought the car that if i kick the car into overdrive the oil gage would go up, and i mean right up to the top, i caulked it up to a bad sensor but now I'm not sure, I'm going to put a mechanical one on it to see what happens but i cant find the oil sensor. in 2 weeks I'm driving back to Ontario for Christmas and i don't need this. is some one can help that would be great.

Check with a mechanical gauge and see what you have. The sensor is located by the oil filter. https://www.gmforum.com/t284737/ When the pressure drops do you hear any ticking?

thank dan for the pic its going to help me locate it, and as for any noise, i dont beleive there was any ticking or knocking, but it was hard to hear with all of that RAP CRAP coming from the back seat from my 14 and 15 year old but im going to go out and let the car warm up and see if is going to do it again.

OK just to clarify my gauge, it starts at 0, half is 275 and top is 830. i just started the car (and let me say its cold here) it was JUST below 275, now when i stopped at the red light it went all the way to 0 and it done it about 2 or 3 time and no more after that but I'm going to get the car warmed up and see if it does it again but what about it going all the way to 830 when i floor it.

i went out and and got the car to operating temperature, showed a drop in pressure it sat between 0 and 275 which is half way on the gauge, put it into drive and it dropped to the red and the " check gauges" came on, do i really need to do a pressure test on it or is the motor gone. i have no pinging or knocking that i can hear but i have a small exhaust leak at the y-pipe to the manifold

If you have zero oil pressure you would hear tapping because the lifters would loose oil pressure, and the rockers would be tapping on the valves. Sounds like a bad connection. Check the plug and clean. I don't believe it is actually loosing oil pressure. I will assume you checked the oil level.

ya i checked the oil as a mater of fact i done an oil change 3 weeks ago also i let the car run for about 3-5 mins with the gauge in the red and i didnt hear no tapping, pinging or knocking

I had this same issue on my 97' over the summer it got bad to the point of dropping to zero at every stoplight and dinging.

replaced the sending unit, and that made it not hit zero anymore, my gauge still bounces all around during operation, I have no idea why but I've put many, many miles on it since then. I seem to remember someone posting a long time ago that there is a little spring behind the oil filter adapter that wears out and can cause the gauge to float around but I've never looked into it myself.