You might pull your fuel line to the carb, have someone crank the engine (or turn on the key if electric fuel pump) and catch a sample of your fuel in a mason jar. Swirl it around and any water will be spinning at the bottom of the vortex. If you see any water then a jug of Heet will likely be your cure. Have you isolated it to a specific cylinder, or just noticing a miss? I'd pull the plugs and see how they look - could have some rust/corrosion from an idle winter, especially in an unheated space. What's your distributor/ignition system? Another thought is to start it in the dark and look at all wires/coil for tracking & sparks. I remember my first old chevy used to put on a light show under the hood at night before I learned that was not normal....