Intermittent fault. Bike won't rev past 6000rpm

[ogri48]

I had an issue just like it on my thou to do with induction, but I know youve already checked that. The power cable for my garmin has an inline box built in about  the size of half a fish finger. It had moved around under the seat and partialy fouled the airbox trumpet. ran perfectly to 6k, then four stroked like buggery and died