Thanks for the suggestions so far.
I have tried running the engine with a different exhaust setup (a two into one exhaust manifold with a single muffler for both cylinders) and haven't noticed any improvement (still misfiring at no load and fouling on that side). This should eliminate the individual muffler as a culprit I think.
Still looking for ideas. I will definitely post back if I do figure out what it is!
RLP
