sprint 955i misfire

developed a misfire/hesitation over 2000rpm,changed plugs and replaced coil packs with s/h units,changed fuel,checked vacuum hoses,fuel filter changed in dec.really annoying now as bike has never missed a beat for me in 5 years.milage is 38500 valve clearances done 3500miles ago.anybody got an answer.

 

thanks for reply,i now have had engine management checked out with nothing showing,ran fuel injector cleaner through tank.have now drained out fuel tank and cleaned out all fuel lines and filter.some muck in tank.bike feels more responsive but still have a low down misfire around 2ooo rpm in 4th gear but revs lovely above that.hopeing that my local dealer can pin point problem this week as booked in for an hours diagnostics.thanks again