Long-time lurker, first time poster.
I've just resolved a problem with my bike which I wanted to share to help anyone who might suffer similar symptoms. It was bought new in 2015 and has just over 50k km on the clock.
The bike started showing a FI light warning after riding about 20km. When the ignition was cycled it would start normally and the warning would disappear for a short period before reappearing. Sometimes the engine would behave normally after the restart, other times throttle response would become very choppy - riding at 30-40km/h in peak-hour traffic became a nightmare but highway speeds were fine.
In dealer mode it showed the error code C17 (Intake Air Pressure Sensor).
After much frustration checking connections etc I eventually removed the vacuum hose that runs from the throttle body to the sensor (Suzuki Part # 13683-48G10).
At the bend where the hose joins to the throttle body, the hose had what looked like a bubble in the rubber and was very soft - a bit like a bruise on an apple. I cut it open and the inside lining had perished and almost gooey. My guess is once the engine temp heated it up the vacuum would collapse the hose, blocking it.
Since replacing the original hose with some vacuum hose I had lying around, the error is no longer showing up and the throttle response is much smoother.
I hope this helps someone avoid similar frustrations.