I did some research for you about tunes and gas etc... This is common for people who use low grade gas or not high enough octane for the tune. Not saying thats what you did but these symptoms are.. What gas station are you using? Are you sure the tune was for the 91 tune? It was only a short period of time but I ran the diablo intune 91 tune and had no issues and when i checked my plugs they were damn near perfect. I only ran Sunoco or Mobil and beat the piss out of the HEMI to be honest..