Bit worried about mine, it does chuff when I'm on 10 tenths. When you say full treatment what does that mean mate?You can use your treatment in a more aggressive way if you run the fuel as low as you dare (light on at least) then add the full treatment to the empty tank, go run it hard at full revs until you're on vapour then fill up and add another treatment in.
Also, you can get a smoke reduction treatment to add to the tank. mine blew a 0.97 with a bottle of wynns in the tank at its last proper MOT![]()