BMW has downgraded its fuel-economy ratings for the 2012 328i after the Environmental Protection Agency published lower figures during its own tests, the company said Wednesday.

The 4-cylinder 328i automatic, which BMW had estimated and promoted with a 24 mpg city/36 mpg highway rating months earlier, is now rated at 23/33. What's strange, however, is that this is the exact rating for the 300 horsepower 335i, which has a larger 3.0-liter inline-six engine.

"This one is kind of an aberration," BMW spokesman Thomas Plucinsky told MSN Autos. "It doesn't fit to what we see in real life."

The EPA requires automakers to conduct their own fuel-economy testing, and only audits 10 to 15 percent of all new cars each year. While ratings can and do change after initial estimates, they typically only vary as much as 1 mpg up or down.

BMW said the EPA tested the same 328i that it used during its own testing. The EPA does not allow retesting during the same year. The manual-transmission 328i is unaffected, at 23 mpg city/34 mpg highway.

Initial media reports about the 2012 328i praised the turbocharged 2.0-liter sedan for besting the EPA highway and combined ratings of the 6-cylinder 335d, a diesel model that was offered in limited numbers from the 2009 to 2011 model years. The new 328i features an 8-speed automatic, which still handily beats the previous car's 18/28 mpg rating and its 6-speed automatic.

[Source: BMW via Autoblog]