98 Legacy OBD2 code P0420

The car has 150,000 Km's (90,000 miles?). It has been flawless, until the MIL - P0420. Subaru dealer wanted to play "Replace parts til he's broke" I have changed the rear O2 sensor, now have a new catalytic converter. I do not wish to just keep throwing parts at it. I thought that a Subaru dealer should have the equipment to look at the ECM inputs and O2 outputs, etc... HELP... if anyone has experienced this or something like it, I would appreciate any help. Where do I go from here, BROKE ??

Reply to
Edwin NoSpam
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What does that code mean? TG

Reply to
TG

OK, low catalyst efficiency. Usually replacing the exhaust manifold gaskets will cure this. I like to replace or at least chase the studs, you need an accurate torque reading here. Check for any other exhaust leaks upstream of the O2 sensors. TG

Reply to
TG

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