I've got the same symptoms. The above suggestions didn't fix anything. If the lift pumps were not sending enough gas, you wouldn't reach WOT. They could be leaking into the intake if the diaphragm is bad...you could loosen the 2 mounting bolts and see if fuel drips down. I have good pressure in the low side and high side fuel systems. All filters are new and O2 sensor is new. I've tried 2 sets of plugs. I'm completely stumped and caving in and taking it to a Yamaha Master Tech. I'll try and let you know what the problem was once it's fixed. I hope it isn't the Stator coil...they are $500! My plugs are usually wet with oil after I run it...so for some reason I'm not getting good combustion at low speed. If i get it above 1500 rpm, it'll run fine all the way up. Once I bring it back down to idle it'll start sneezing and sometimes die. Good luck...I need it.