The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Engine cuts out after driving 20 min, ideas?

franken · 04-21-2021, 11:18 PM

Just a guess but maybe take the gas cap off when it happens.
I think 71 had the vacuum canister to vent the gas tank into the intake rather than into the air. If so the gas cap would have originally been unvented.

04-21-2021, 11:18 PM	#3
franken Registered User Join Date: Jun 2013 Location: Somewhere Posts: 3,057	Re: Engine cuts out after driving 20 min, ideas? Just a guess but maybe take the gas cap off when it happens. I think 71 had the vacuum canister to vent the gas tank into the intake rather than into the air. If so the gas cap would have originally been unvented.