I had the cel/miss fire issue on my 2013 5.0 m6 base. Car went back to the dealer 6 times before the o ring on the CPS was changed. That fixed the issue. I believe there is a TSB for this fix now too. If not have your dealer do a hotline request into engineering and also call your area CSM/CRM. Both tsb's the TSB 13-01-11 didn't work for me
2013 5.0 m6 base 3.31's tint 20in Shelby razors 255/35/20 falken fk 452's koni srt.t's sr springs j&m phb gt500 mounts upr rear billet lower ca's upr brackets upr adjustable upper ca flowmaster at classics steeda cat deletes airaid cai premium st brace jlt catch can MGW shifter and blk ball. Currently bama tuned 400hp 383tq. Zex blackout kit w/msd digital window switch, fpss, zex bottle heater, bottle opener, blow down, and purge with a dyno tune coming soon..