What Non mopar mechanic work are you doing

Putting new coils, plug wires, double sea foam treatment in my 2007 GMC 1500 4wd 5.3. It's sluggish, misses, lost power.
Went from 15 mpg to 10 !!
I'm Dyed in the wool Mopar but an LS is hard to beat for $ per horsepower and durability.