Ok, so..

If I put in supreme, after 3 or 4 tanks, the vehicle dies directly after filling.. due to flooding.. I am a tech, and know that if you go past the first click and continue to force fuel in, it will force fuel into the EVAP system and cause flooding, but this happens even after just $5 of supreme, and from different stations (companys), the flooding is from, what I am assuming, the EVAP system, I get no codes, so, I made a ritual of getting gas at a gas station with a straight away that leaves there with no stops to burn it out.. I assumed it was a bad EVAP canister or purge valve..

BUT.. when I switch back to regular it doesnt die anymore, this has been going on scince the car hit 1000 miles or so,(directly after a one time use of fuel attitive, for an autocross event, never used scince, but thats when the problem started) its been a year, and I can verify at this point that the different fuel types cause these different effects..

any clues??

 

What type of fuel addivtive? What do you mean by flooding? That supreme fuel just dumps directly into the evap canister?


A faulty purge valve would not cause a runability conditons. It would trigger P0446, p0441, p0440 codes. Evap canister could cuase this if you overfilled. But it is more than likely related to your fuel additive.

What have you gone through in your diagnotics? What are your fuel trims?

Octane being a cuase factor is highly suspect, the problem has to lie elsewhere, i say this because it makes no sense as octane cannot cause such an event.