Ok so not exhaust getting plugged.
I had similar issue few years ago. Short overview of my issue...
Rode 40km to the hills sled ran fine, get inside doing a climb and sled didn't have power to climb out. Was popping and felt like water in gas.
Get out to warm up shelter put gas line antifreeze in, was there for maybe an hour. Leave to go home and sled ran fine all the way home( trail ride).
Fast forward to the next weekend, same thing.
Get home and was ready to remove tank and clean it out. (But did not, looked fine)
Got a coil from another sled and swapped it through, still acted up.
Gets almost home and check engine light comes on and code, forget now, it was few years. Get off and fool with harness and sled shut off! Oh no! Fooled some more and heard fuel pump kick in so starter it and went home.
Finally was ready to order a new harness for it, thinking my season was over it was late in the year.
I go inside all discouraged have a coffee and some lunch and say to myself nope not done with it yet! I go back out in the shed take the air filters off and start taking the harness out of the sled and find rub through right on engine jyst behind primary clutch. Aha! Fix up wire that is rubbed, tape up wire put back in wire casing, tape that, put loom over harness and reinstall and run sled. Fixed the problem.
Also have heard of wire rub issues in harbess on brake side. Check that out too.
