It's worth checking the rear diff and gearbox, both seem to be expensive potential issues and weaknesses with the 6, might be worth getting the oil changed in both just to make sure all is ok.
Will be very interesting for you to update us in a month or so with your real world MPG.
Well worth doing, no idea why Mazda fitted the odd tyre size to both the 6 and 3mps.
Thanks, will keep an eye on them too and I will make sure both have their oil changed next week.




