Questions & Answers for: Subaru Forester lambda

...confirm? P0420 is one of two things, it is either a catalyst failure (below threshold) or rear lambda. The rear lambda should have a steady waveform when the engine is running if not then P0420 ...

...and intermittent poor idling.High emission CO output when warm = 5 or 6.0.Spark plugs replaced,lambda sensor also.cataclean used.Next would be engine coolant sensor. no fault codes found when ...

lambda 1.116 test says it is running too lean Vac leak? check o2 sensor wireing & plugs, Also visualy look at all wireing espesially HT leads, Batry red + plastic cover, Washer bottle lid (Mice ...