Just had a 500 cooler, T34 .63, light blue 400 injectors and chip fitted to 4x4 cossie and still have an issue in that under full throttle, normally in 2nd gear, if I floor it, it tends to miss. If I build up slowly all OK, but on full throttle it often does this. It did this before the conversion when I was on 330 kit. I've had an issue before with plug gaps causing this, but it did this after a rolling road tuning session where I know the plug gaps were altered. Sound likely, or change plugs, leads etc??