I suggested in your other post about doing youre plugs, this is for the same reason you have here- I had the same problem, and sometimes it would sound like your going hard and really you could be getting smashed by a lancer... LOL
Gap & re-place your plugs, and you wont have that problem- another suggestion is if your run a washable POD then do it, and while your there, clean the face of you air-flow meter too- between those tow probs, you can double your power (well,at least double what your used to being pissed off about- lol)
Let me know how you go?