Check the ignition coil itself, the one your plug wires connect to. When those go bad or wires get lose it kinda acts like you describe.
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I had a problem with one of my 07 600s when the left side controls would get wet it would either die when let off to idle or it would shift in and out of reverse continuously took my switches all apart and dielectric-ed everything and put it back together and the problem went away now I keep the sled covered to and from the hill when on my sled deck.