I have a 2015 Challenger RT 8/A which just had a comp cam 270 installed with all the supporting mods i.e. Valve springs, retainers, pushrods, MDS delete lifters etc. I also had a set of kooks long tubes and catted mids put on. The shop that did the install used Johan for the tuning and it took almost 40 revisions and the car still doesn't run at 100%. It still starts hard, surges at idle and while driving, won't idle at less than 900rpm or else it stalls or kicks me out of drive, and feels like it's misfiring down in the low range but no codes and I had the shop install all new spark plugs and o2 sensors. I'm also getting severe driveline whiplash downshifting from 3rd to 2nd if I'm not shifting manually which is the same gear change that makes it stall if I have the idle set to less than 900. Does anyone have any suggestions or similar experiences? Maybe I should switch to HPTuners instead of my diablo tuner? I'm out of ideas so any help at all would be greatly appreciated because I'm sitting on an entire forged 392 Stroker kit that I won't get installed until the car is running the way it should.