I bought a 2007 Silverado Z71 shortly after ( i still had my old ford though). The Silverado had under 36000 miles and it burnt a quart of oil every 1000 miles!!! 2 GM dealerships told me it was normal. One dealer said it was due to low compression rings they are designed that way!?!! hahaha. I was so mad, i sold the silverado and decided to dump the 20-30grand in my old ford instead! Once a Ford man always a ford man. I now have a brand new red F150 STX 5.0 as well. :-)
Yep, GM had major issue with oil burning in those motors, especially the 07-08 yrs with the 5.3L. It was actually an issue with faulty design of pan and not have a windage tray in the oil pan, oil was being slung up in cyls and getting past rings. My coworker was burning 3-4 gts of oil every 3000 miles in his '08. They installed a windage tray, fixed the oil burning, but then there was an issue with poor casting of the block where intake bolts on.....he ended up getting a brand new motor out of it.
That's cool that you were able to buy the truck back and have your high school vehicle.
I sold my first vehicle, '72 Cutlass, in '1998 as parts car due to rust, saw it last year on CL...or parts of it. Kid I sold it too parted it out immmediately, the guy who bought the parts put them on CL 13 yrs later.