Hi, was after a few ideas of things to check with my r33, the problem is soon as it starts boosting up it missfires to the point it just doesn't run, just coughs and splutters, this happens at about 4 psi, as soon as i back off runs perfect. Things i have tried to do to rectify the fault is change, ecu, spark plugs (all came out totally black), afm, cas, ignition relays checked, igniter (the earth seems good too, I asume its the one that goes under one of the coil holding frame bolts), JJR coils went in about a week before this happened aswell. I haven't yet pressurised the system to check for air leaks yet but all the cooler pipes seem well sealed.
cheers