2003 Chevrolet Avalanche Problems

I would want to know what the actual oil pressure is. The sending unit or the gauge on the dash could have failed.
There is a pressure relief valve to prevent oil pressure from going too high, but staying at 80psi would not be good for a long time.

On top upper side of bell housing on the engine. This page has a diagram and info.Look for the red arrow

http://www.2carpros.com/questions/chevrolet-avalanche-2003-chevy-avalanche-oil-pressure-sending-unit

The oil pressure gauge on my 2003 Avalanche reads "0" and activates low oil pressure warning. Oil level is OK and engine does not sound like one with with no oil pressure; AKA no knocks or ticking. The mileage is 50,000 on this vehicle any ideas as I with no gauge I am leary of driving it? Please advise!

Common problem on the 03-06 Avalanche instrument clusters, it's caused by failing stepper motors on the cluster's circuit board and it can be repaired. Check this page for more on how to get it fixed - Avalanche oil gauge fix

Sounds like the oil pressure sensor. Thatt is the easiest thing to change. If not its the gauge. Put voltage to the wires from the switch and see if the gauge stops jumping and stays pegged, if it does its the switch Good luck

Check the oil pressure sensor..

Pretty common problem with these. Here's a guide to learn how to fix GM instrument clusters yourself, I used it to fix mine and it worked great.How to guide for Avalanche instrument cluster repair

If no codes or check engine light, then I'd start by changing fuel filter. When was tune-up, & filters changed last?

the sensor is located at the back of the top of the engine, behind the distributor. Could be the sensor or the gauge itself. Probably the sensor stuck.

GM had insturment cluster problems 2003 to 2006 . Inside is a part called a stepper motor , this stepper motor controls the gauge position .
How to repair GM Instrument Cluster Speedometer Gauge Stepper
Beside's the stepper motor issue there can also be a problem with something called silver migration , this has to do with the solder used in the insturment cluster . This can cause a number of electrical problems most people would not even think possible .
Silver Migration
Watch this two videos .
Chevrolet Truck Battery Dies Overnight Part
Chevrolet Truck Battery Dies Overnight Part II