Backfiring on deceleration is often a sign of a lean condition. I suspect on your Jimmy it's because of no muffler. It could be a carburetor problem or intake manifold leak or other issue. I seriously doubt the ethanol has any role in your issues.
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
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