What is the spark plug gap for a 2004 1.8t VW Passat Wagon?

The recommendation may vary according to the plug manufacturer. Try the manf. own website (NGK and AC Delco have Excellent info, for example) and have your engine type (first three letters usually required) to hand to help your search. If that is no help then I would set at 1mm or 40 thou. (yes, I did mean a really big gap!)