I have a 2015 Polaris Sportsman 570 EFI with a cold start issue. When left overnight or for a few days, it'll crank and sputter, and eventually start. After it is warm, it will start right up all day long with no issues, with the exception of occasional backfiring when letting off the throttle on a descent. Runs fine - snappy acceleration, no bogging down, no other issues...... just a real bear to start when cold. It's not bad gas, as I ride it regularly and have turned the tank volume over at least 5-6 times in the last couple of months. Air filter is new, so not clogged or restrictive, and the battery is fresh and reads ~13v. The machine does not throw any codes.

Interesting to note that if I squirt some starter fluid into the air intake before a cold start, it fires right up as it should. So, that leads me to believe there is a lean cold start issue, but I'm not sure where to go from there. Temp sensor on the cylinder? Injector? ECM issue? Any and all help/suggestions would be appreciated.