Another thing that happens with the car, is when the car is on overrun going down a hill or incline etc, when you step back on the accelerator the car will missfire for a bit. It did this the other day, when I took the plugs out, plug number 2 (the one that has melted the tip) was covered in oil and had quite a bit of carbon build up. could this have something to do with the tip melting? I've put a set of 071's in that I had spare, and im just driving the car steady, trying not to put it under load or bring it onto boost etc