I can almost guarantee you that a failing MAF- Mass AirFlow sensor, is your problem. You can do the "unplug test" to narrow the possibility that this is the problem. Unplug the MAF as shown in the pic while the engine is OFF. Then, drive it normally, prefferably only around town. If you notice a distinct and immediate power increase, then I'll bet you it is your MAF failing. (Unplugging it forces the motor into "limp home mode," which actually isn't bad). Please note that a failing MAF does not necessarily make the "Check Engine Light" go on. If you unplug the MAF and drive it, the "Check Engine Light" will come on once normal operating temperature has been reached. No worries- It will reset itself after 3 ambient to operating temperature cycles and no sooner. (Provided the ECU, (Electronic Control Unit, or Brain, has detected NO fault, and you have re-plugged it in correctly). That means if you RE-plug your MAF and take 5 short trips where the temp never reaches "Operating Temp," the light will not go away.
Try it! It may just be your problem. You don't state the 'mileage' on your car, so I can't say whether or not you are eligable for the VW extended warranty on the MAF- (It's a known problem area). I'm not even sure it's available to Canadian cars. While you're at it- If you're unfamiliar with the issues regarding a plugged "snow screen" and soot build-up in the inlet manifold after the Exhaust Gas Recirculation Valve (EGR)- Perhaps now is a good time to search on these topics, for they can sometimes produce similar symptoms, but chronically, not accutely.
