I just bought a 2017 GMC SLT with the 6.2L and 8 Spd. It had 8700 miles on it. It will idle a little rough at idle momentarily. I only run premium gas, is that normal for the 6.2L? I've installed a Magnaflow 12909 muffler w/o flapper valve and an AFM Momentum CAI. Also, since I've had it, it has a tick that is heard when your standing next to it, or in a drive thru with the window down. Is that normal? After reading on here I'm worried about the afm lifters causing it. I plan on getting a Hypertec programmer so I can change the afm to 70mph and adjust the shifting so it's less clunky. I also will be installing an Elite Engineering EX-2 catch can kit. Will these additions help with the common afm issues? To make it more reliable in the long run? Anyone with experience or knowledge please educate me on this, thank you