Probably a combination of factors. Canadian elections, OBL's offing, and lower domestic demand.
Seeing as it took three months for pump prices to run up to where they got, I'm not expecting to see 'em fall back overnight. Around here prices have fallen $.10 in the past 3 days.
Part of the problem in the Chicago to Milwaukee corridor is a federal mandate to use seasonal reformulated blends. This [censored] has been in effect for 25 yrs, and somehow we always get smacked with a 25 cent increase every Spring as the refineries somehow haven't noticed this requirement after all these years.