[ewalberg]

DITTO!!! Headwinds/Tailwinds, and drafting other cars makes big difference... i notice mine is pretty bad too when cold, but i sure like the more agressive shift points when cold... at first i thought there was something wrong with my tranny till i read the manual and it says it lets the engine rev up more between gears when cold.

...and intuitively it doesn't make sense, but technically it's possible that the car and trailer is more aerodynamic than the trailer alone, depending on how the car ocupies the low pressure space behind the vehicle.

heck, just sitting at a traffic light for a little too long on a 25 minutes drive could make all the difference.