2001 vw jetta gs :check engine light goes on and off

sounds like a faulty sensor tripping and reconnecting.. the next time the light comes on, take it to an advance auto store or an auto zone, they can read your codes for free... this will tell you what is being tripped, that way you know exactly what you need to get checked and/or fixed instead of a mechanic poking around trying to find everything thats NOT wrong. but if you are not expeiriencing any difficulty with the car, you should be fine. the check engine light actually means alot less than most people think. its usually a transmission or emissions sensor, or even as simple as leaving your gas cap off after filling and then driving for awhile.