91 octane

I was using octane booster with a few tanks in a row, and now when I go WOT I am seeing positive knockr on my nguage. It is usually negative at anything less than wide open. This all makes sense; but how would I go about resetting what the ecu uses to guess octane, or should I just keep...

Esp as it relates to boosted applications, all stations in my area are 93E10, except one that is a VP distributor and they have 91E0. For DD use, is one preferable over the other? The 91E0 is $0.25-30/g more than Exxon/Texaco/Conoco/Valero.