Hello to one and all.I am very knew to this site,I hope that someone can help me ,I drive a 2001 Road King classic,Efi,I just installed a KN high air flow filter and the pipes have been changed also,I just had the bike remapped it ran good for 2 weeks ,then started to foul my plugs again with a lot of back firing as I let off the trottle, going down a hill,also is it worth installing the power commander,so that I can set up the fuel and air mixtures thank you Ken