pd (pumpe dusse) is the new tdi engine. Still 1.9 liters, but with a different fuel pump(s) and injection set-up. The rotary pump is gone and has been replaced by "unit injectors" or basically there's a little fuel pump at each injector. Stock power is up to 100hp and 177lbft, it meets tier II emissions requirements, it's a little quieter, it's a little smoother, but fuel mileage is down 2-4mpg.