Re: 115 Ficht Exhaust sensor
Lower stb. side of the engine block. Follow the small hose from the engine's computer down to the fitting.
IF it hasn't been removed for cleaning every 100 hours as required, then it may be partially burned away or jammed in the housing with carbon. In extreme cases, you have to cut off the threads and carefully drill out the tube. Then remove the carbon. Use a 5/16" valve guide brush for cleaning out the cavity.