First off all afm lifters have been changed, recently I had a misfire on 7 that caused stbilatrac code to come on, took to the shop and the truck decided to quit misfiring on the way there, and act right. Two weeks later misfire on 7 again same situation but after having a computer hooked up to it and deciding we should delete the afm, the Truck starting running fine again the next morning, but it now has a Thumping noise from the back of the motor that doesn’t seem to be coming from an internal part of the motor. It also made this noise when the tech was turning the afm on and off with his tool. It will stop if I turn the truck off and re crank but starts back up after a few minutes.