High idle...

[chandlerbingfl]

Hello fellow owners! Not well versed in bike mechanics but when I started my GZ this morning the idle was pretty high. Probably close to the 3k-4k mark when stopped. This never happened before and when I would turn off the bike it would pop/backfire. I checked the manual posted here but not quite sure what to check. Is it the screw w/ the white knob on it? That looks to be a stop for the throttle but when I tried adjusting it did nothing. I did turn it but put it back in the same spot, still no change in idle. Up till this the bike ran perfectly...

Any suggestions? Like I said not much experience so any help will be appreciated. I know the choke is in the "off" position and was wondering if this might be "on" even though it is "off"... maybe a stuck cable?

Thanks in advance!
chandler