91 octane tune - which order? fill or tune?

blackened · 08-17-2005

I'm almost out of 87 gas and i'm looking forward to the 91 tune... should i run down the 87 tank as much as possible and fill w/ 91 then while at the pump put in the 91 tune?

OR....

should i let it run a bit w/ the 91 in the tank then do the tune?

I don't mind wasting a few bucks on unnecessary octane but i do not want any pinging.

thanks in advance for you input

junior · 08-17-2005

I could burn a tank of gas in 2 hours if I desired. I wouldn't put the 91 octane gas in until you tune it. The tuner doesn't know what's in the tank, all it does is change the computer to THINK you're running hi-octane.