power loss after exactly two weeks. '12 Charger SE

[cq842000]

So no matter what I try, if I load the "Diablo" tune and add some MBT WOT and some WOT or even if I dont and just run the untweaked canned tune, the car runs great for approximately two weeks then starts to lose power, no LTKNK or STKNK over 2.5 except on rare occasions @4.5k RPM, no codes, no dash lights Iver targeted a 12.87:1 AFR through datalogs though I dont know how accurate stock o2 sensors are. This has happened consistently for the last six months. I return to stock but it does not fix this and it continues to lose power. Everytime the dealership flashes factory software the car runs great until tuned. Already replaced one PCM. If there is anything I can do to get this issue sorted please help me help you. Or if you have any ideas about what might be happening I would appreciate it. I am seeing desired FA of 15:1 but actual is no more than 14:1 at low RPM cruising, and also I'm seeing short term negative fuel trims of 13% and short term positive fuel trims of 15%, yet 1/1 and 2/1 long term fuel trims remain at 0 and never change... could this be a fueling issue?

So I ran my old timing advance numbers and datalogged and observed some stknk retard, I'm thinking maybe I'm suffering from the effects of LTKNK Retard so my next question is after I get my timing advance down and get rid of most of the STKNK Retard, how long before the timing that was pulled by presumably LTKNK Retard gets returned? Pulling the negative battery terminal for 30 minutes doesnt seem to affect this.

[mikel]

if you go back to stock and it continues to lose power, it rather clearly says it is not an issue related to the tune....

[cq842000]

if you go back to stock and it continues to lose power, it rather clearly says it is not an issue related to the tune....

Where do you think I should look? As it only starts happening after I program it then drive for a couple of weeks. Also when I said it continues to lose power, I meant that it runs like a dog and doesn't get any better until the dealership flashes the factory software which obviously I cannot keep doing. I cannot see stored codes with the intune dcx, but the dealership can.