First I wanted to say that I watch many of your videos on Youtube and I have to say you have helped me out a whole bunch on so many occasions! Thank you.
I was wondering if you can help me out because I am kind of desperate. I have a 2008 Honda Civic Hybrid with about 157K miles on it. A few months ago my check engine light came on and I used my scanner to see what the problem was. It was a P0420 code so I checked under my car and the Cat appeared burned and was deteriorating. So I replaced the Cat, resonator and the muffler, both O2 sensors, engine air filter and all the spark plugs since it was time anyway and the car was hesitating when I accelerated (I did this all myself watching some of your videos!). The hesitation went away only after changing the spark plugs but the P0420 light came back on after driving it about 150 miles. So I purchased the Bluedriver and did a smog test on it and after clearing the code and driving it a about a 70 miles to get the monitors ready, the Catalyst test and the EVAP test was not complete. Then after driving it another 30 miles, the check engine light came on again with the same P0420 code. The only thing I have left to do I think is to see if there's any leaks in the exhaust system. Is it ok to use a shop vac to push air into the exhaust pipe to see if there's any leaks? Would it damage the system in any way? Also, if I find that there are no leaks, what could possibly be the problem? If you can help me out with your expertise that would be awesome Scotty. Thank you.