0-320 fp, carb, dual pmags. Happened twice. Engine performs normally in the pattern, but when I’m cruising at 2300rpm’s or so and advance the throttle with mixture leaned I get real rough running to the extent it feels like it’s going to quit. As soon as I pull back the throttle everything goes back to normal. I also enrich the mixture. At first I thought it was a slug of water in the fuel so I checked that after the first incident and there was none. I am of the opinion that there is a issue with the carburetor, the acceleration pump. But I am open to any suggestions.