I jut picked up a 03 jetta 1.8t and it has a bov on it an air intake and a cheap aftermarket muffler welded on. The day after I got it it threw the code. I work from home so I haven't driven it much. The code said it could be
1: the engine is running a lean fuel mixture
2: possible vacuum leak
3: rear o2 sensor.
I already had the exhaust checked and no leaks. I'm thinking I need to change the bov to a dv and that would fix it. But maybe it is tht I need the spacer on the cat since the exhaust is aftermarket. If its jut the o2 sensor I'll change it. What do y'all think?