i seem to be eating a ton of fuel, and you can smell that my car is running rich. how can i check if for sure that its running rich? i have no check engine or anything like that. i do have a laptop with the vag-com software, can i check from the com? if i have a problem, what could it be? oxygen sensors? thanks

 

Very likely that O2 sensors could be going bad - over time they will carbon up from use and will lose precision. To play things safe, most cars are programmed to richen the fuel mixture when the O2s start acting "funny" (ie, not indicating within a certain expected range) - if they get too bad and/or fail completely, the car will run on a preset program that calls for excess fueling to protect the engine (without reliable feedback from the O2s, they'd rather run the engine rich and foul plugs, than run lean and end up with mulched rods or other such damage). I would imagine vag-com would allow you to watch/log O2 sensor data.

 

If you are running very rich, you will notice black smoke behind your car when you are at wot. You could also pull out your spark plugs as an indicator.

 

could also be a maf sensor