[Hal Copple]

i get much the same problems when "winter gas" comes out in the fall, when my car is hot, it boils and percolates in the carb, floods, stalls, and in general makes my car quite cantankerous on a warm fall day. Once i get up to speed, and get some cool airflow thru the engine compartment, it is ok, and when it is cold out, it is not too bad. But i just detest traffic when i have a tank of "winter" gas. I run some race gas added, but generally i just swear under my breath at how lousy it is to have a boiling carburator.

After four years, i can tell precisely when it comes out in the fall, and when they go to the summer blend in the spring. My guess is that this is your problem.