Talking out my theoretical <img src="/forums/images/graemlins/butwiggle.gif" alt="" />...

If he has changed nothing about the running, then something has changed on him, right? Under that assumption, wouldn't backfiring mean fuel that was perviously delivered and burned, is now delivered and not getting burned?

Shouldn't he pull the plugs and check condition there? What about the dizzy? When was the last tune up?

Could a bad coil (single, not the 3x2-packs) cause this?

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