Well, today we set out for a cruise in the country to pick up eggs, drive for 45 minutes at about 45 mph, come up to a stop sign, the way is clear, leave and proceed and the CEL lights up!
Pulled over and connected my OBD II reader, and it's the P0420 code back again, so I believe the oil and condensation that was getting into the throttle body via the hose to the valve cover is most likely not the cause of the code, it might have been from last year or so, but who knows.
Plan B install the O2 sensor spacer to move the second or after catalytic converter sensor back out of the exhaust flow in the pipe, this should stabilize the readings to the ECM and stop the P0420, this is s test, I am not saying this is the cure, just a test. I'm going to try the spacer setup until April 1, 2017, and see if that stops the code from returning!

Wow edge of your seat tension , much more exciting then that ball game last Sunday !! Well maybe for some.

 

That is the circumstance that P0420 test runs. As it comes to idle the computer diddles with the A/F then measures the lag at the #2 sensor. It is in milli seconds.

It is a test of oxygen storage in the catalyst.

 

Ok, then we're gonna test if the position of the #2 or after catalytic converter O2 sensor is removed from the exhaust flow, will it change anything at all.

 

I installed the spacer , just one, I drilled out the centre hole to 1/2 inch, installed a crush washer, no codes since I cleared them on Tuesday the 8th, let's see what happens.
Now this spacer moved the O2 sensor out of the exhaust flow , the O2 sensor was very clean looking no corrosion, no caked on soot, or crud, fingers crossed

I'm sorry I didn't take pictures, the driveway was wet from the 40 degrees weather melting yesterday's snow storm!

 

Alright then, two days 175 miles, so far no pending codes , no mpg issues, no drivability changes, and no pesky P0420.
I'll check in next week with an up date

 

Here is a fairly easy to understand description of what the PCM is using to throw a P0420.



Without a good graphing oscilloscope you can't see what the computer sees. I tried.

 

I'm just testing the theory of the spacer concept, I saw on YouTube a thimble like device called a Tom Thumb, I'm not sure about that , however if I'm still getting the code by April 15th, I'm throwing a new catalytic converter on and calling it a day with this experiment.

 

Took a 175 mile drive in the country, no codes, pending or otherwise!! Stay tuned!

 

Another 200 mile drive along the North shore of Lake Erie to Leemington Ontario, still no CEL!

 

...sorry, I gotta say it: how about finding a closer place to buy eggs! :P