Have 09 SRT Challenger, 6.1, rods, pistons, cammed up, Vortech blower, car runs absolutely great, LT/ST trims are under + or_5% 99% of the time, but after it sits a bit you start it and it's surging and trims head hard north within seconds, it stumbles hard with any throttle input, no codes. Shut it off and restart and cars perfect again, every time hot or cold. It's the same scenario every time it acts up whether it's sat for 5 minutes or 5 hours and not it's every time it's started, but you know right away when it acts up. I can post file and data logs if needed, thanks for the input, really starting to be a head scratcher for me on this one.