Where is the oil level sensor located? oil guage wiggles between 40 & 60 at idle and stays on 60 on the road.

if the guage is unreliable and its the only one that is, may switch to an aftermarket separate oil pressure guage that mounts elsewhere and be done with the situation entirely..these run around 25 bucks and its time to install and it wont fail like electronic ones do...

if you mean it wont tickover but will rev up ok, then i would suggest throttle position sensor, hope this helps

It is just as likely that the fuel level sending unit in the tank is bad as it is that the fuel guage in the dash is bad. The guage is MUCH easier and cheaper to change; try that first.

Theres only one fuel pump relay, unless you have dual tanks. Be sure you have 55-60 psi fuel pressure. I "think" the oil pressure switch supplies power to the fuel pump after the engine is running.

i would say its a sensor in your tranie

if it shows low oil level its possible bad "level sensor "located on oil pan.if it shows low oil pressure possible oil "pressure sensor"

you have a heavy guage wire that is shorted.did you have any major engine or trans work done?
It sounds like you have a wire pinched in between somewhere.
Check your wire harness pull gently every where this is called a wiggle test.
Here's a nugget for you,do your wiggle test in a dark area if possible you will see a spark.

30 PSI hot idle is ok, 40-50 PSI at freeway speeds hot is good. this is based on using the correct weight of oil which is 10W-30W

Where i s oil drain plug?
GMC 2008 Sierra

Ok not to keen on newer vehicles actually prefer the carburated ones, but oil pressure is supposed increase on your gauge when accelerating. If it wasn't going up before and just staying at 40 the needle might have been stuck. But idle should be 40 lbs and when you work the moter (reving or driving down the road) the guage should show an increase for every 1000 rpm above idle. Second if you can get a hand held scanner (bought mine off ebay for $30) check for any codes in your computer you will probably find that you either have a bank running wrong or some other sensor that needs to be changed. I'd go with getting my own scanner it saves alot of money and time, garages make their money here.