So I replaced all the O2 sensors a while ago and they were GM replacements. It ran just fine too. It has all new GM sensors actually except the crank sensor. I think what did it is I fill up 3 miles from home. I read that it takes 7 miles from filling to learn what it needs to about what fuel is in it and if you shut it down before that it throws it off
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. Either way I’m trying to decide if I want to buy a tuner/scan tool that can just disable the virtual flex fuel sensor and afm or take it somewhere. I got a quote from a shop in Pensacola that was $300. That seems very steep for a couple of mouse clicks in HPtuners.