Yukonxl2000

Good morning everybody,
Last night I got the dreaded oil pressure light and a flat out 0 on the gauge . I never had any oil pressure issues on my 2000 Yukon with 225000 miles ,she doesn't even take oil.The weird thing is on the second start up the oil pressure goes right back to 40 psi?!?
This morning I started it up again same issue ,turned it off instantly and restarted tada 40psi and ran fine.I was planning on buying a long block engine from summit racing in the fall because of the high mileage,but my budget now doesn't permit this!
My question is what are the odds it's the following and what would you put your money on first?
1il sending unit and screen replacement
2il screen pickup tube o-ring
3il pump failure?although it pumps on second startup
4: just suck it up and admit the engine is done time to change?
5: it's been awhile since oil change 800miles, I'm using AC delco filter and castrol gtx high mileage oil / change again?
6: check valve in oil pump unit?

oldchevy

Try a mechanical oil pressure gauge just to verify that your reading is correct. Might just be a faulty gauge.

cleveland63b

sounds a lot like a sending unit problem but its always a good idea to put a gauge on it to make sure