Check to see if the choke is sticking on the carb ? That and go vacuum hose leak hunting. Get a bunch of hose and replace everything. Not that expensive and will help. Either of these will make any VW run like crap.

98 Mystique GS V6 - K&N, projectors 91 Mustang LX 5.0L 00 Jetta TDI, Yay, I bought it !! 95 VW Getta TD - RIP: Nov.3,2005