During the past two weeks my fuel economy has dipped by at least 5 mpg
on my '08 OBS.
I live in the Chicago area where it has been snowy on the roads and
the temp has ranged between 0 and 20. The average MPG read-out starts
out at 19 when I add some gas to fill the tank and then within a few
miles, dips to 17 and basically won't move by more than 1 mpg or so.
That read-out is accurate, I calculated it the old fashioned way and
it was also 17. The TPMS alerted me to pump up the tires a few weeks
ago and now they are at the levels as listed in the owners manual for
winter conditions.
I am a conservative driver (as much as possible when driving on snow
covered streets)and just a few weeks ago, I was getting 21 to 23 mpg
and during the summerit was reaching 27.
Any thoughts would be appreciated.
Jeff