Poor little fella. You could take apart the exhaust and look for it but he might be snared up irretrievably in the muffler, meaning replacement. I don't think he could plug up the exhaust but my experience is rather limited with chipmunks. Try goosing the gas one good time in park, maybe that will blast him clear, (stand back while trying this) Or, drive on the highway for awhile he'll eventually dry up and and stop smelling. After all there can only be so much smell in one little chipmunk. I have heard of a gas additive that will make your exhaust smell like pina-colada. Hope this helps
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