carburetor heat shield

The float stuck & a bit of dirt in the carb, thats what I think. Sounds like a similar happening to me one day.

I pulled into a 7-11 one day and the second before I pulled in, the car did just what you describe. Acting funny out of no where. Hit the gas and the response was a lame return, way way down on power. Opened up the hood to see the drivers header super bright cherry red.

Took off the air cleaner, reved it up, shoved my hands over the carb and choked it out.
(After several tries and a few good hits to the side of the carb) Started it back up and it was fine. You could hear it run better. Header glow went away in 3 seconds.