Have you looked at the other Cylinder Tops?.. Are they the same? If it is only one cylinder, then you have an injector that is flowing less.. If it all of them, then you have a Basic Lean Condition that should be addressed. No Injectors are Immune to Fowling.. Fuel will clump up and plug things.. I think ECU Talk will read the O2 Sensor Voltages on a 96.. you want O2 Voltages of >.8 when in Boost