Hey Scotty, first off I want to say I think what you do is awesome and that you help so many people like myself. I’ve ran across a problem in my 2013 Tahoe with the 5.3 (afm). The truck seems to idle fine other than the rpm’s fluctuating up and down about 200-300 rpm’s but my big problem is (don’t know if it’s supposed to run like this) when driving at any speed, under acceleration not full throttle but more like half, the truck seems to bog down on me. It kicks down a gear like it should but almost immediately after hitting the gas the rpm’s come up to about 2,100-2,500 rpm’s but then immediately bogs down to about 1,200-1,600 rpm’s before it finally starts picking up speed again. I’m absolutely clueless and have googled everything under the sun. I hooked a scanner to it (I have no check engine lights on) to watch the fuel trim and noticed under throttle that my fuel trims are dipping down in the -8.6 to -12.2. I honestly thought it was a clogged catalytic converter but after a month of searching the web and no avail I hollowed all my catalytic converts out (still no check engine light) and it still runs exactly the same. I’ve had a 5.3 (non-afm) and it’s never felt so weak like the one in my Tahoe does. I have a afm/dod tuner plugged in and have also tried unplugging it and still nothing. Plugs and wires have been changed, I’ve also cleaned the MAF and butterfly on the throttle housing and still absolutely nothing, tightened all my air duct clamps to make sure no “extra” air was getting in as well. So far all I know is I’m running rich. I can’t even tell you if there’s even a problem, I don’t know nothing about the 5.3 flex fuel with 6 speed to tell you if there just weak drive train in general. I just know it feels like something is off. PLEASE HELP