Almost certainly not caused by the ethanol. Cheap, nasty, dirty fuel is cheap, nasty, dirty fuel regardless of whether it has Ethanol in it or not. Unfortunately, a lot of our experience with ethanol blends so far is with it being used to reduce the cost of fuel to the consumer - there's no thought given to quality above a bare minimum in this case. On the other hand, Shell Optimax Extreme (you can get it at the Shell service stations on either side of King George's Rd just south of the Hume Highway) is 100RON and is being marketed as a premium quality and power fuel, with ethanol used to pump the RON rating up from 98. Shell are charging a premium for this , so the quality should be there. It's the same fuel the V8 Supercars will be running this coming season, and while race engines to get rebuilt regularly, I can't see them being happy running fuel that's likely to gum the engine up and seize exhaust valves... I ran a few tanks of Optimax Extreme in my RX Liberty, and my highly reliable "seat of the pants meter" said it went better - the engine seemed more responsive, and even sounded fractionally better. I want to do a blind/double blind test or at least dyno the car on it and other fuels before I'd recommend it though. Just need to find someone doing a dyno day on a AWD dyno...
