Start with the easy stuff. Fuel injected bikes need a good strong battery to stay firing. Have yours load tested (free at autozone & most shops). Replace if necessary.
I would probably get some starting fluid and spray a small amount around in different areas near injectors while it is idling to see if you have a vacuum leak. Hell I dont know what else to do. Just read dcline9163"s post tps could be it but I thought they wouldn;t run at all if tps was out of wack[safety reasons]
Fuel octane would not make a difference. All 87, 89 ,93 etc contain up to 10% ethonal. I have seen (on fuel injected bikes) the hoses inside the tank swell and rupture or even pop off the fuel pump/filter. If bike starts and sputters it sounds like a fuel psi problem. Thats just one possible thing. Check the basics. Fuel spark air.... If youve got all of that then your problem lies deeper.