2004 Volkswagen Passat starts but lacks power blacksmoke

replace fuel filter and add some fuel additive should help

sounds like you have possibly got a split or disconnected turbo pipe check around the under side of the turbo to the intercooler and under the passenger side headlight where it leaves the intercooler also make sure you see the actuator arm on the turbo lift when you get someone to start the car for you if it dont check all the small vaccum tubes normally black in colour post back if you have any joy