Ive got a 95 trueno gtz that keeps failing the nct because the CO reading at just under 3000rpm is too high. Now if you bring it up to 3050rpm its perfect but the nct centre won't do this. Does anyone here know how I can bring this reading down. I've tried butchering my air filter with a Stanley knife to leave more air in and it helped a bit but not enough. Is there any way to ingage the supercharger at say 2500rpm just for the test so it'll lean out the mix. Any advise would be much appreciated.