Volkswagen: vw problems, mass air flow sensor, mass air flow

Question
I have a 2001 VW jetta (2.8L VR6 model). It only has about 43,000 miles. The engine light had been on for the last few months and the dealership told me that it was a faulty coil pack. I changed that but the light came back on again within a few hours of driving. Then they told me that I needed a 40K mile maintenance (that costs $650). When I looked at the book the only thing they do in the 40K mile maintenance is change the spark plugs. So I got them changed at another auto shop and even got the engine tuned. But the light came back on again. The engine runs real rough and the EPC light and the traction control light come on when I am trying to accelerate. Now I found another auto shop - and they just told me that the cylinders were misfiring and I might need a new "mass air flow sensor". Could you plese tell me if this is the case? Is it common for a car with so few miles to have so many problems? I have already spent about $800 on this car in the last 2 weeks. I have already replaced so many sensors on this car before.  

Answer
thr air mass meter can cause running problems and cause the lights to come on, but obviously i cannot tell you that is certainly the fault. Just a silly question, do the brake lights work? and as for the engine tune, everthing is electroniacally controled so there are no real adjustments that can be made. another common problem is the engine coolant temperature sender going faulty, as this alters the fueling for hot and cold running conditions. the result being that it over fuels or under fuels the car. lambda sensors can also cause running problems and lights to come on as it gives incorrect readings for the burnt exhaust gases telling the car it is over fueling or under fueling.