Have a 2008 Electric EZGO which "hops", even on brand-new smooth asphalt roads. All four 12" tires just replaced as one-year old tires were found out-of-round by tire dealer. Recently had cart dealer use hand-held device to update/adjust the controller or chip (or whatever). Did get a slight speed increase but notice battery power goes down quicker also. The "hopping" or "jerking" has to be something other than tires or rims, but dealer doesn't think anything mechanical or electrical can be wrong.....any ideas on what to have checked out?