I had suggested to him a while back he may wanna run some gasoline every once in a while. He has a FF tune and an E85 tune. He just didn't. His symptoms started with stalling at red lights. He started with having injectors serviced (they were fine) then replacing fuel pumps, FPDM, something on the TH hat that's different from Challengers, and finally took it to a shop. He texted me pictures the other night and the fuel lines had some kind of sludge in them. Says now he wished he'd run gasoline occasionally. I just shot him a text to see what's up with it now. YMMV as they say but I'll run 93 through mine once a month just in case.