Car is a 2001 Volks GTI with the AWW 1.8t, stock K03 turbo and all, chipped. Don't remember offhand who the chip is from.

Problem is: At low/no boost, runs perfectly fine. Original problem occurred whenever any boost more than around 4-5psi hit the engine, it would cause a loss of power and a repeated misfire from the same cylinder.

We took the plugs out, checked for any problems, found none, and shortened the gap on the plugs to just slightly below manufacturer's spec's. Afterwards car runs solidly and pulls hard until you put the pedal down hard enough to reach 13-14psi and then causes the same rapid repeated misfires as one cylinder essentially stops firing.

I have a strong idea of what the problem is but I want to hear what some first-thoughts are from you guys in case I'm wrong about it, and to see if we're essentially barking up the right tree.