I have a 2010 5.3 6 speed that i can't figure out what its cousin the negative timing. I went through the six speed tuning class but i did not like that it say to disable the upshift torque management, and that's the only thing that would help not to get negative timing on shifts. Other thing when i go WOT timing drops and slowly starts going up. Now this a 4700+ lb's truck and would not like to disable upshift torque management, I did it once and this thing felt like it slip 3rd gear
It's a 5.3,boost cam on 15 to 16 lb's of boost.
Here's a log the only one i have saved because i run out of fuel pump. On this one i have the timing at 8* but only get 6* and i don't see timing till around 5800 rpm's.