[Doofus McFancypants]

I searched for this but did not find what i was looking for.

Was talking to a co-worker today - had mentioned the ECO driving and how well i am going with it - he mentioned to me that the best time to fuel your car is 1st thing in the morning with your tank no more then 1/2 empty ( or was it 1/2 full )

He went into some longwinded explanatuon about the fuel vapor pressure and the additional "liquid loss" after the tank crosses the 1/2 way mark as "gallons you can't use"

Then he told me me how the 1st thing in the morning - the liquid is more dence in the colder temperature - thus the volume of a gallon is less

the first one i could almost follow him - almost made sence - except for the Emissions testing we undergo in Georga - they check yoru gas cap for proper seal - so the Vapor can't escape - so is it really lost?

The second point just seemed plain wrong to me - may be it was his argument - but could not see how temperature could change it that much.
( would your swimming pool "overflow" in the afternoon if you filled it up in the AM)

Anyway - i wanted to see if either of those had been discused - I could have missed it when i searched for them - and if this has been discussed - My apollogies for the repeat of the subject

Thanks
Steve