I think not. With a full tank there is less room for fumes to expand. I believe less fuel in the tank means worse fuel economy. Found this[1] from a quick sear

I think not. With a full tank there is less room for fumes to expand. I believe less fuel in the tank means worse fuel economy. Found this[1] from a quick search. [1] https://www.carsforsale.com/how-to/5-simple-reasons-to-keep-your-gas-tank-full/#:~:text=A%20lighter%20load%20does%20require,fuel%20tank%20is%20not%20significant.&text=per%20gallon)%2C%20so%20even%20in,tank%20can%20increase%20fuel%20evaporation https://www.carsforsale.com/how-to/5-simple-reasons-to-keep-....