Maybe the car is trying to tell you something:
Maybe it doesn't like the ex.

kidding

Mine was acting up sort of the same a few weeks ago, first fire up of the season, ran terrible, same kind of symptoms....found a tiny piece of translucent plastic stuck in the needle and seat. Blew it out, and it was perfect after that.

This might sound silly but make sure the oil hasn't got contaminated with all that fuel.