Are there any recalls concerning low oil pressure

Did you find out what was wrong with your chevy? I have a 08 LTZ with 156k on it and I started having oil pressure issues last year. When it would get below freezing my oil pressure would get crazy and drop for no reason and when I rev the engine it would go back up. I got the oil changed and it fixed it for awhile... eventually I replaced the oil pan gasket and the rear main seal, it hadn't done it since until last week when it got below zero I was driving down the highway and it went to ZERO and would come up when I reved the engine. I have read the oil sensor/snder unit screen gets clogged up or the unit itself goes bad. My mechanic replaced the screen and it is still acting up. I got my oil changed at firestone tires last and I am sure they used cheap oil and filter so I am having my mechanic replace the oil dender unit and give it an oil change... hoping that is the problem. Truck has been amazing, I have had it since it had 40k on it and have had no issues.... so this is frustrating as I decided not to trade it in and just replaced a bunch of front end stuff shocks etc. I really hope its not a engine needing to be replaced!!