Back Story
Recently my bike had an issue twice while riding that the throttle seemed like it was sticking. I'd be accelerating and when I let off the throttle, it would continue to accelerate. It happened the first time a few weeks back (not sure if it could be related, but before it first happened I installed a new gear indicator), on the street (in traffic), and I immediately grabbed the clutch and rolled the throttle back and forth to get it unstuck. To my surprise it seemed to operate just fine, but rolling off wasn't getting the RPMs down - they were just sitting around 4-6k RPM. So I hit the cut-off and pulled over. Shut the bike off and fiddled with the throttle some more. When I turned it back on, it was fine again. Then, about a week later, it did the same thing.
Now last week, it did it again, but it hasn't unstuck! I limped it to work and decided to come back to it later.
At the end of the workday, I decided to check the throttle components. The first thing I found Google'ing the issue (and this had several different people experiencing it and apparently there was a part changed between 2013-14 to handle the problem) was about one of the throttle cables slipping out of its channel and becoming stuck. So that's where is started to look, the cables right off the handlebar. They all seemed fine. Everything seemed to sit right and it auctioned just fine. Then I took a look at the throttle body pulley while a friend rolled the throttle, again it rolled just fine. Then I started it and had my friend roll the throttle a bit too. It started just fine, spun up to about 4.5k RPM on its own, and then seemed to increase and decrease properly based on throttle action.
I haven't checked anything else yet, but I'm not really sure where to start.
So, summary:
Basic Problem
Bike revs to 4,500+ RPM without any throttle input.
What I have checked
throttle cables
idle adjustment
throttle body action
What I'm thinking to check next
air filter
TPS
oil (and filter)
fuel with injector cleaner
vacuum lines
throttle cable adjustment (if there is any)
So, if anyone has other ideas to contribute or can recommend things to check, I'm all ears! Since I didn't expressly say it, the bike does have EFI and it's a little past 12,000 miles overall.
Also, as a note, I've always been quite punctual about following the periodic maintenance chart, and have only ever used 91 octane, good quality, gas.
Finally, this is a California bike, so it does have a couple small differences from the models elsewhere, though I don't know that they would make any difference to the problem.
As always, I GREATLY appreciate any help, and thanks in advance!