Oil Level Low???

[Armyfoo]

I have a '07 Sierra 5.3 alum engine that has been giving me oil issues for the last 5000 or so miles. Quick run down,

 

Last month, dash began telling me the engine oil level was low, and also began to lose pressure. Pressure level normally runs 55lbs. But driving from home to work is a 30 mile trip and the first day I noticed this, I was almost to work, came to a stop at a stop sign about 1 mile from work, and my oil dropped to appx 25-30lbs. Check engine light was NOT coming on with the "oil level low" display. So I said to myself, Oh well. I am at work now. I will pop the hood and check it tonight. Amazingly enough, NOT LOW. Started the truck, pressure went straight to 55ish lbs or pressure. Let it idle and warm up to 210 and still held high pressure. Drove home and about 5 miles from home at 65 I was pulling 40 and lower lbs. Engine was due for a oil change anyways, I began thinking restricted oil filter.

 

I use Royal Purple (truck has 140k miles, money isnt a concern when it comes to my truck) and changed the oil and filter as usual. Low oil went away and pressure back up to 55-60lbs.

 

Now for the issue at hand.

 

I am only about 2000 miles into this oil change and the truck is saying low oil level again, AND noticing about 10-15lb drop in pressure. Once again, I checked the oil on a flat surface at full temp and the level on the dipstick is maybe 3/16" ABOVE the full hole on the stick!!! What is causing this "level" problem?

 

I have already read the entire thread about the oil pressure switch screen/filter but nothing was ever mentioned about their oil levels. Any ideas before I begin throwing cash at a garage?

[00Silverado4x4]

It's possible the oil level sensor in the side of the oil pan or it's connecting wires may be messing up. I'd start there myself.