Intermittent spark

I have an 06 Polaris RMK 900. I recently was riding and my sled started backfiring and bogging down. It now won’t start. Sometimes I have spark and sometimes I don’t. I have replaced the ECM, new plugs, new coils, new voltage regulator, new stator and new flywheel. I’m still not able to get it to start. Some days I get spark and it will start. Some days it won’t. Any suggestions would help. Thanks! Snow is falling and I’m stuck at home!

Sled is at Polaris. They have gone through everything in the last two weeks. Sled has spark, compression, fuel, and air. Still won’t start. They have given up on it and have asked me to come get it..... any suggestions would be great! Thanks guys!