The pump/regulator died on the way home the other day. Not totally but I could only surge it by letting it almost coast to a stop and then goosing it up. GTS250 had only 6000 miles so this was a disappointment. I bought the bike as a demo off the floor so I'm supposing that at some point, it was allowed to run out of fuel. NEVER try to limp an extra mile on an empty tank with any type of fuel injection! the fuel lubes the pump and lack of fuel will soon kill it.
FWIW, mine was giving hints starting a couple of years ago. When I would come to a hard stop, the engine would surge at idle and not settle down until I shut it off and restarted it. This spring it seemed to run rough and lack power at full throttle. It was hard starting the day it quit. Apparently it was pumping some fuel and that's why I could restart and make a few more 10's of yards each time. It would build pressure as it idled but use it up at more throttle.
Cost of the repair was ~$650, ouch! The pump/filter/regulator part that came out was the most Rube Goldberg device I've seen in a long time. Why Piaggio didn't use something off the shelf baffles me. I was going to replace the parts myself but a quick inspection revealed the cunning engineering that went into the pump and tank placement: the engine needs to be dropped for access! I used an alternative method of work and stood back and threw money at it. Works fine now