After Changing spider unit with mpfi unit truk started right up ran sounded felt strong better then ever shut it off started it up later in day completely opposite,ruff idle nasty exhaust smell trouble code p0200, so took off plunum again,(maybe I pinched a wire or something) put it back together, started it up ran real good again shut it off started it up again a little later ran bad againany ideas on why this is happening thank you very much