Sounds like you may have been a little lean up top.

 

Its having EXTREME fluctuations on the MAF readings. That could be part of it. It pegs 50# of air at the 1-2 shift, but pulls a steady bouncing 35-40# in the upper rpms. I've never seen one read that irratic before. It could be all those 5#+ sudden changes in the air the PCM thinks the engine is getting that causes the burst knock.

 

Oh yea, it is funny that your cammed and stalled LS1 had trouble pulling on the big ole' Yukon. Did you mention my trailer is more than twice the size of yours too? hahahahahahahahah

15 second big body's RULE!!!!!!!

 

it ain't that much bigger but i did pull the infinity last night though.