[Curt C.]

I have been thinking about your problem and while I am certainly no carb expert, I will try and comment. It seems very weird that one bank is rich and not the other. The fuel gets atomized and then sucked into the cylinders. As a result, I would think that lateral G's would not have too much effect on the A/F mixture. Have you checked your fuel mixture screws? Maybe the passenger side screws are too far out - fat causing the right bank plugs to run black. Does the plugs exhibit the same condition just driving on the street? Interesting problem.