Questions and Answers

Chevy Truck Exhaust Backfire Problem Q. I have a 1968 Chevy truck with a backfire problem. I have recently gotten this truck as part of my father's estate. It has driven well for about a week but has suddenly started backfiring (actually, exhaust explosion). There is no carbon evident in the carburetor so I suspect that there is not a true backfire.

The POP happens on deceleration (even when slowing to cruising speed from acceleration). Any help will be appreciated.

• 1968 Chevy C10
• 250 cid 6 cylinder)
• Manual 3 speed transmission
• 280,000 miles
• Carburetted
• P/S, A/C

Thanks,
Alan

A. Could be a dwell problem with the points. Is there any pollution stuff on it? A bad diverter valve used to cause backfire on coast down. I'd start by checking for play in the distributor shaft and put a new set of points and condenser in it.