Ok guys,I have a problem.I bought my GTA from a second owner in January,He put new tires, new front suspension and gave it a full tune up last year.I drove it up to Minnesota to paint it at my dads shop,all you can get for gas up there is ethanol and it hasnt run good since,It starts and idles fine,smells kinda funny,but has a slight miss? or kinda chugs going up hills.Ther weird thing is it runs even worse if it is a quarter tank or less,it runs like its a v6.I need some ideas guys,I am new to this third gen !