In recent news Volkswagen has admitted to using special software settings that resulted in better fuel economy and performance for its diesel cars that were being tested. The special settings used during testing vanish when the car is driven on the road, resulting in nitrogen oxide emissions up to 40 times the federal standard.

In response to the scandal, Consumer Reports conducted new testing of 2015 and 2011 Volkswagen TDI diesel vehicles in this “cheat” mode to assess fuel economy and performance. Throughout the testing they found a noticeable decline in fuel economy for both models. Their testing also showed reduced acceleration with the 2011 models, which are equipped with a lower-tech diesel filtration system.

VW has yet to announce the specifics of the recall to fix its 482,000 diesel-engine Beetle, Golf, Jetta, and Passat models in the U.S. Consumer Reports will conduct another round of testing once the cars have been repaired or updated.

Stay tuned to MotorWeek for more details.