For a few months now my 2010 S has been getting harder to start. Its cranking longer and longer before starting, then when it does start I have to idle it up or it will stall. It used to run fine when it was warmed up but now even when its warm it starts to lope and will some times stall. Off idle it runs fine all day long and it doesn't seem to be down on power either, it runs fine at WOT too. I hauled it to Lake Tahoe this weekend and it cranked so long on sunday I didnt think it was going to start. The air filter has two rides on it, checked it anyway and it looked fine. Installed new NGK BKR7EIX spark plugs last week and rode around my house a little, made no difference. My machine has about 1500 miles on it. Sugestions?