I am experiencing exactly the same symptoms. In the summer I had the 96000Km service(so new spark plugs and wires). Even before that, I noticed that quite randomly, but never when cold, I couldn't accelerate normally after stopping at a light. I could not predict though when it would happen. Last month it was worse and worse, the frequency of loosing power at lights or after reducing speed was higher, and finally it started to misfire and backfire when I insisted on pushing the gas pedal to get higher than 1000-1500 rot/min on tachometer. I cannot elaborate technically as I am not that qualified. I was able to start just fine at -25C. But after the engine got warmed, it started to stutter. It has periods of running perfectly at high speed e.g 110Km/h, and then stutter. At such high speed it seems to be better because it just recovers quickly, but at low speed, especially when idled, it is just like not all the cylinders work. It helps if I keep it on park at lights and push the gas from time to time when I fill it starting to stutter so that I get more than 2000 rot/min. I suspect some kind of a clot along the gas tract from the tank to the engine. But that might be of course over-simplistic. I also considered that the air/gas ratio not right, as I get a strong smell of unburned gasoline. I booked a service next week. I also need to replace the muffler, which I new I should for few months already.