Do I need to replace the Catalytic Converter in my 2005 Toyota Highlander V6 2WD?
2005 Toyota Highlander V6
217,000 miles
Maintained at the dealership until Dec. 2011
One very loving owner. Bought her brand new with 17 miles total including my test drive.
Background-
Time of purchase through the summer of 2009: All routine maintenance was done at the
same dealership.
2009-2011: Moved to Austin and took it to one consistent dealership.
Aug. 2011: Replaced all the O2 sensors
Went into the dealership for an oil change and tire rotation on the way home all the lights
came on. Called them right then. Went back the next morning. No clue what the code was
but replaced the O2 sensors. Toyota did not verbally tell me and the paper work is long
gone due to a misplaced box after a move.
Dec. 2011: All three lights came on again. Code PO420
This time Toyota told me I needed to replace the Catalytic Converter. I refused and
traded cars with ex. He drove my car for two days and the lights went off. It passed
inspection. I traded back. I love my Highlander and his Camery is kind of a snooze fest.
Feb. 2012: The lights came on again. They had been on and off since then. Not sure if
this will help my case or make me sound nuts but...
*For months the lights would turn off if my car was really dirty and I drove through a car
wash.
*Then it completely switched and they would come on if it rained or I took it to the lake.
I know, I know, I said it was going to sound nuts...
Sept 2013: They have been on full time going forward.
November 2013: Lots of various codes (all related to the catalytic system). Replaced the
Spark Plugs and still had lights. Replaced the Mass Flow sensors and the lights went out.
I drove 100 miles and the lights came back on. Guessing the computer just caught up...
I took it in today: The codes were PO430 and PO429.
My gas milage has recently gone done dramatically (16 mpg) but I am not feeling any
performance issues. I am pretty sure you are going to tell me to replace the Catalytic
Converter(s) but I was curious if it could be anything else? I was also curious which side
of the engine bank one is on (since the PO420 reading had to do with bank one)?