Bad throttle response
I have a Gsxr 750 k9, the problem was when dropping down from 3rd to 2nd it was impossible to roll on the throttle smoothly, it went from nothing there to lurching the bike forward.
There was also flat spots in 4th and 5th at low revs when cruising and just rolling the throttle on.
Anyway checked for any info in the net about the TPS or O2 sensor as I thought I may be that.
By chance I came across a throttle free play video, adjusted it as recommended and that fixed it all.
Just wanted to put this up in case it helps anyone.