Hey Scotty I have this 2009 Subaru forester 2.5 X premium. It has 193,000. the check engine light is on, i looked at my scanner and it said P0420(1/1) Stored Catalyst System Efficiency Below Threshold (Bank 1) Severity 2 of 3 Freeze Frame//// ( note the check engine light only comes on when I am going a certain speed) what do you think I should look for?
If you live in a state that does not do emission inspection, leave it alone. If not, try some catalytic converter cleaners (e.g. CATACLEAN).
Take it to a dealer and authorize them to look at it (but not fix it until you get more info). Some Subarus of that vintage have a lifetime coverage of the catalytic converters and offer replacement at no charge (I don’t know details other than it has to do with CA emissions; if yours falls under that, the dealer should be able to tell you).
P0420 is covered in the FAQ
