Final answer:
Using gasoline with alcohol in warm weather can lead to vapor lock due to fuel vaporization in the fuel line, affecting engine performance. It may also cause phase separation in the fuel tank due to alcohol's tendency to absorb moisture, leading to starting problems or poor engine run.
Step-by-step explanation:
Using gasoline with alcohol in warm weather can cause certain issues with the engine performance of a vehicle. While the content of the fuel blend may not directly affect engine driveability, the presence of alcohol can lead to a higher likelihood of vapor lock, which occurs when the fuel vaporizes in the fuel line rather than in the engine combustion chamber. This can cause the engine to run poorly, stall, or be hard to start. The tendency of alcohol to absorb water from the atmosphere can also lead to phase separation in the fuel tank if the blend is left to sit for extended periods, especially in warm weather when evaporation rates are higher.