I have always filled my car with 91 non-ethanol for it's entire life with me (5 plus years) Recently my local station began carrying 87 non-ethanol so I decided to try it since I'm running stock. Since that fill-up I have experienced hesitation under full throttle acceleration and the occasional stumble. Last year I had similar problems when it was damp out thanks to a cracked rotor cap, crappy spark plug wires, and a tired ignition coil all of which I replaced and had smooth sailing for the rest of summer and fall. It has been rainy here lately but I really can't believe it's any of those parts at fault again.

I have nearly burned up all of the 87 and just refilled this morning with 91. I'm curious to see if the fuel is the cause and if anyone else has experienced anything so dramatic from a change in fuel.