VW hesitating when accelerating

Getting on the freeway today in my 2000 VW Jetta, my car hesitated repeatedly as I accelerated, then my check engine light went on flashing. Once I reached cruising speed, the car stopped hesitating, and the CE light went solid. The CE light's been on since then, and the car does the hesitating thing every time I ask it to accelerate more than a little bit at a time (does it coming off of stop signs/lights, getting on the fwy, etc.) What is this, most likely? The car was just serviced last week and has about 111,000 miles on it.