BMW S1000R engine/power/feul surge at 6000rpm

Engine light (yellow) was on when i turned on ignition, the bike wouldnt start. So i turned off and on again. Engine light gone and she started. Buuuut on the road at exactly 6000rpm there is no power and sound like feul surge or something because i could not accelerate more. Below 6k rpm she is all good. Turned off ignition again and on. All good.. Its the second time this happened. My thoughts it could be feul pump. Lose connection.l or something. Just to add. All is stock i only did a decat about 4-5 months ago.