Motor shuts down

[Lenny Bruce]

Hello everyone! My question today is…What would cause my Model A to shut down for a second or two and then fire back up and backfire? I’ve checked the gas flow to the carburetor and it seems nice and strong. The car seems to be under powered at times and then out of the blue it will cut out and then reignite
And Boom!!! Can it be a stuck valve? Any input would be greatly appreciated.
1930 Sport coupe. Thank you