You might want to check the other side of the dash to see if the Temperature gauge has also quit - both the Fuel gauge and Temp gauge are on the same circuit, so if
BOTH 'fail' at the same time, it's probably a circuit related issue, maybe a fuse, relay, or a wiring short, etc?? But if just
ONE of those two gauges has failed, I'd guess that it's more likely to be that gauge itself, or possibly the sender for that gauge.
I hope, for your sake, that it's not the sender - getting the gas tank out far enough to access the pump/sender unit is not the simplest of tasks, and then there's getting the fuel pump & sender unit out after that, fixing/replacing whatever the issue is, then you hafta reverse the whole process!

However, while doing all that yourself is a bit of a pain and takes a fair while, but if you hafta pay someone to do it, don't think that'll be any less painful, cos it'll really hurt your wallet instead!! Because it's not a quick & easy job and it takes a fair while just to get the tank out far enough, the time involved adds significantly to the labour costs involved!
There is already a little bit of discussion to be found here on the Forum if you search for it, not much on actual 'failures' tho, but that's starting to change now that some Spyders are getting on a bit, racking up the miles, and components are aging/wearing...
Good Luck!
