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**Papa Smurf** · 12-12-2010, 11:01 AM

I recently had the exact same problem with my 72 c20 work truck. Try spraying some Berryman B-12, or similar, around the intake manifold. If there is a leak, it will pick up RPMs with the spray. Mine was leaking. Raplaced gaskets and torqued and it runs like a champ.

12-12-2010, 11:01 AM	#5
Papa Smurf Active Member Join Date: Feb 2009 Location: Ben Wheeler, TX Posts: 131	Re: Back firing and Missing Please help I recently had the exact same problem with my 72 c20 work truck. Try spraying some Berryman B-12, or similar, around the intake manifold. If there is a leak, it will pick up RPMs with the spray. Mine was leaking. Raplaced gaskets and torqued and it runs like a champ. __________________ 72 Sierra Grande 2500 BB 72 Sierra 2500, 42K miles, factory buckets 72 Cheyenne 20 72 Chevy SWB, Factory BB, Leaf Spring