If this is the case for you guys, there has to be something wrong with mine. We're deep into summer and my milage still hasn't gone back to what it was last summer when I bought it. I still often am getting 6- 6.5 l/100 km in decently hot weather for an hour highway drive and it will still do the thing it started to do in the winter where it showed a crazy mpg at the start. It didn't do that last summer, starting directly in decent milage estimates. I've gotten it back down the 4.8 on a 3-4 hour drive but that doesn't compare to last summer when I was routinely getting 4.2-4.6.

What could be the problem?