Help my 08 1200 Sport with 2013 Griso engine and drivetrain has developed a problem . It starts and idles fine but when you open the throttle it only runs on one cylinder. If you slowly roll the throttle open, no problems It has 47,750 miles on it, 5000 miles on the fuel filter, Power Commander 5 with auto tune, open air box and open exhaust with no catalytic converter.
It started bout 100 miles ago with a slight hesitation when accelerating and has been getting worse.
Any Ideas on where to start?