My mods as listed below if that need be known. My truck had run strong(for a 6er) for a while until about a week or two ago when I noticed a very slight "chugging" upon acceleration in the lower rpm range. It also lost what little pulling power I had in 4th and 5th gears....5th is flat out terrible now. The engine light was not on but I scanned it with my Hypertech. It found several codes..p0102, p0113, and another one I cant remember. Both of those relate to the maf sensor. Maf low input and iac temp is too low(shortened abbreviations). Would that indicate a bad maf? I only have 20k miles. Oh and now the engine light stays on. It kinda started when I started using Shell gas...have it tuned for premium. Anybody have any ideas?