Hello. I have a 2008 Subaru Tribeca (~150k miles) and I have a check engine light that comes and goes at relatively random intervals. When it does come on, it reads as P0420. After driving with it for about 100-200 miles, it'll go away. Around the same interval with it off, it'll come back on again. I just wanted to check if there were exhaust leaks before spending $700 on a catalytic converter because I have no decreased fuel efficiency, no sulfur smell, and no noticeable loss in power. Turn on the car, check engine light on and says P0420. Leaf blower the tail pipe with soapy water and found no exhaust leak. Start the car with a little trouble, but eventually starts and no lights. Is it the O2 sensor or is it actually the catalytic converter?
What makes this problem better or worse?
Random, but seems to stay off longer when I'm in a lower elevation
How long has your 2008 Subaru Tribeca had this problem?
Professional quality scan tool is required for *hands-on* testing - which is the ONLY way to discover the actual failure - online guessing isn’t beneficial.
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