According to the official listing at FuelEconomy.gov, the 6-speed manual 2009 VW Jetta TDI managed 30mpg on the city cycle and 41mpg on the highway cycle, making its combined number 34mpg. Now those numbers are certainly respectable and nothing to sneeze at, but they fall well short of VW's predictions. Nonetheless, the TDI rates 41.7-percent better than the 2.5L five cylinder and 36-percent better than the 2.0 TFSI four cylinder. The big question is what will a diesel Jetta do in the real world?
Official EPA numbers posted for the '09 Jetta TDI - 30/41mpg - Autoblog