Must be the cold weather, my OP gauge started maxing out last week. Changed the oil and filter out of paranoidia, and it had no effect. I believe it's either the gauge or sending unit. Truck runs like a top.

 

Okay, I have searched the internet all morning looking for something similar, and this thread is as close as I can get.

I bought my truck (2005 Chevy Silverado Z-71 4X4) used, June-2011, 82,000. Since I bought it, the oil pressure gauge on the dash has read 80 PSI, MAXed out. In Aug this year, the oil pressure gauge began to drop, jump back up, etc... At first it was once. This last week, it had "yo-yoed" back and forth, mainly after the first start up? I have had my oil changed, or have changed it myself using Pensoil Ultra synthetic 4 times in the last year. There is no knocking, tickin, or other noise when the gauge drops. It stays up after the truck is running a few mintues. The bad thing is it's intermitant.

Not sure if it matters, but within the same day of this happening, my Mass Air Sensor lite came on, FIRST (had it read by code reader at a shop). Within a few miles, the oil pressure dropped, then rose again. It didn't happen for a couple of weeks, then one week, it did it twice. The next week, maybe 4 times. And like I said before, it's becoming a pretty constant thing lately?

The Mass Air Sensor seems to have a mind of it's own? It comes on, goes off, sometimes 3 times in a day?

I am begining to think there is a ground problem, or short in the wiring harness. Again, I had NEITHER of these problems unitl the Mass Air Sensor light came on. No other codes are read?

Can anyone HELP with this problem? Pressure sending unit? Oil gauge? Wiring?