I could use some help reviewing my logs to diagnose drivability issue with low power and mpg cruising at 70mph . I have a 2010 Silverado CC 5.3 6-speed 3.42 with 33x12.5R20 tires and a leveling kit, muffler delete, Spectre CAI (dry filter) and 157k miles. Not expecting to win races or get 30mpg but I currently get 11-12 mpg cruising at 70 on flat Illinois highways. I average 13-14 mpg with 50/50 city/highway driving, so it seems city mpg is significantly better than highway. The truck also won't hold 6th gear in the slightest head wind or minor uphill climb. The truck had issues with oil consumption, to the point of fowling the #1 plug every 500-1000 miles. The TSB work to replace the valve cover, soak the pistons and add the oil diverter in the pan seems to have corrected those issues. I am suspecting skewed MAF or O2 sensors but don't want to just throw parts at it. I swapped the MAF with a 2013 truck but didn't notice a difference so I swapped back. Log and current tune are attached. I've done a lot of reading on this and other sites. I have some questions...
1. Do the LTFT look normal? -10 to -16 at idle and -6 to -7 cruising at 70
2. Fuel pressure starts at 58 but quickly drops to 43 and stays there, is that normal?
3. Should commanded EVAP purge be 100% the entire time while driving?
Thanks in advance.