Notes on DTC P0420 and spark plug changes

[4Aaron GE]

At about 117k, my car would intermittently throw a P0420 (low catalyst efficiency), but more recently it became an ongoing issue. I was looking into working on that part of the exhaust when my friend suggested a spark plug change. Sure enough, I was on original plugs (122k km), and they were quite worn. 70 dollars and a few hours of swearing later, no more DTC! Make sure you check that first!

Notes on the spark plug change:
-The Mastercraft Maximum long impact sockets are just long enough to reach the bolts holding the intake manifold on. If you use a swivel head breaker bar, it'll just clear the manifold without interfering with the hood latch.
-The 14 mm spark plug socket from Canadian Tire works fine for the HR16DE. Way less expensive than the fancy ones. However, I had the opposite problem than the people in the reviews. It held on to the plug too hard, and kept pulling the socket off my extension. (My friend said to tape the socket to the extension next time)