[lumpy]

hi hope any one can help me I own a 2001 bugeye i have not used the car for about 3 weeks as been crazy at work etc well went out today and the battery was flat got friend to help with jump leads started straight up let the car warm up 10 mins then took a drive to garage to fill up fuel was not low on fuel but put 20 pound of fresh fuel in car and now its idleing high at 2000 rpm but it boosts fine and drives spot on but when coming to a stop it splutters a little then when stopped sits a 2000 rpm the car was driving spot on before parked up ive drove car for about 20 minutes to see if it will adjust but nothing any help or info would be great thanks