I can only say putting a free-er can (blue flame in my case) on my old z killed the engine completely until I had the pc installed. It wasn't just 'a' flat spot, it was right through the rev range. I couldn't believe the difference the can made either, but as soon as the pc was on, even with a standard map, it was significantly better than stock.

MM - waiting for ebay might be better idea anyway given the day's revelations! >