I'm struggling with my Passat. It has been very consistent in getting ~32 mpg tanks (I know, it's not in the 70s like a Blackfly
). I've even gotten excursions as high as 39+ mpg for an hours drive. Lately, I've been unable to maintain that mileage and yesterday I got only ~27 driving home. This morning I could barely get ~28.5.
It was raining both times (though that usually doesn't make that big of a diff.) Tire pressures are up there. The engine seems to be running smoothly and up to proper temperature. Possibilities may be the gas, or the coil pack (a chronic arcing problem with the VR6 engine). It has new ignition wires. I'll have to 'mist' it while it's running.