04-06 gets better MPG 07-09. Why?

[RedKnuckles]

What makes the newer engines get even worse mileage. It seems that every year mazda lowered the mpg. Originally 04' got 34 or 35 highway for the i auto, now 09' i auto gets 30.

What gives?

 

[flatlander937]

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles#EPA_changes_in_2008

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles#EPA_testing_procedure_through_2007

There was a standards change around that time, vehicles had to go through closer-to-realistic tests for the published MPG numbers to be approved. In reality there is probably no true appreciable difference, just the numbers changed. If a pre-2007 vehicle were put through the newer tests, they would likely be rated lower.


http://en.wikipedia.org/wiki/Ethanol_fuel

Also in that same time ethanol has been added more and more to regular gasoline. I think E10 is the most allowed... for now(except for E85 obviously... but it is awesome for boosted applications because it is super high octane compared to pump 93) in normal 87/89/91/93 octane fuels. It is basically a bad additive to fuel that helps increase octane but kills the s*** out of fuel economy. The left-wing greeny EPA pricks will tell you "but it's good for the environment and it's cheaper" which is true... but if you have to burn more and fill up more often... then what the hell is the benefit?

So it's nothing that really has to do with Mazda... it's the government stepping in to get their share of the pie.

edit: I hate using Wiki as a "source" but there are plenty of legitimate sources cited in those articles.