My Spyder is driving me crazy. I've been trying to figure out why the engine is misfiring or stumbling whenever I am cruising along at a constant speed. If I open the throttle it immediately cleans up and pulls hard. It feels like its running out of gas like the old days when it was time to switch the petcock to reserve. I've run a couple of bottles of Techron fuel injector cleaner through it. It has almost 12k miles on it so I went ahead and replaced the plugs and wires (Baja Ron, with Iridium plugs), air and fuel filter, MAP sensor vacuum tubes, did the canisterectomy, and tightened the ground bolt under the seat. I thought that I had finally found the problem when I took off the body work and started looking closely at every hose and fitting. I found cracks in both intake flanges so I replaced them. No help it still stumbles while cruising steady speed. As much as I don't want to I'm starting to think about taking it to the dealer and have them look at it. Before I do that, does anyone have any further suggestions?

'08 Spyder GS SM5
'09 Suzuki DL650
Yorktown, VA