When you say the high end screw is all the way in, do you mean as far as the limiter will let it move, or did you bypass the limiter and screw the needle all the way? I have found that with some fuels and some air temp/density/humidity combinations, the Evo's limit is a little restricting. You can move the needle past the stop if necessary.

I had a student with an Alpha that had all kinds of engine running troubles the other day. It turned out that the factor installed fuel tank had split at the stopper a bit and was leaking air like crazy. Apparently the stopper was way over-tightened at the factory.