Mattax said

IF the car is actually having a problem,
A. Buy your hot weather fuel after May 1st. For any car that hasn't rerouted line or exhaust, pretty much done.
https://www.gasbuddy.com/go/summer-blend-and-winter-blend-gasoline#dates-you-need-to-know
B. Anyone saying there is one answer to vapor lock hasn't even begun to know what they are talking about.
First thing is to figure out where in the line its occuring, and under what conditions.
If the vapor lock occurs before the pump is different than if it occurs in the feed to the carb. If it happens while running is different than flooding after shut down - which isn't really vapor lock - and one can use one of the factory solutions of incorporating a tiny relief.
If the fuel is significantly vaporizing in the carb bowl - that's not vapor lock either. Fuel still gets into the bowl in liquid state.

Click to expand...