Put a full can in with a full tank of petrol and it'll be fine, any remaining ethanol fuel will be too low to have any effect it that's what you're concerned about. LiquiMoly is probably the only decent fuel injector cleaner on the market, I used the deep cleanse on a drive up to Sydney. Put a full can in with a full tank and made it to Yass with an average of 11/100 lkm I think by the time I got to Yass there was only about 5 litres left in the tank, talk about cutting it fine. Put in another full tank (I only use premium) in Yass and for the first time ever my Adventra was averaging under 9l/100km unbelievable for a 2 tonne car.