The 2001 Passat 1.8lT has an engine warning light on and feels like it is running on less than all four cylinders.( very rough idle) This is the first time we have seen this particular warning light and the manual suggests that it has a problem with the catalytic convertor.( 170K miles on the car) The car had no symptoms until the light came on today and the car was serviced last week. ( oil change and new tires) It seems that every time I take the car in for service something goes haywire shortly afterward. Does anyone have an idea how much this repair might cost? Also, is this something that can result from mechanic foul play?