Look at post 3 & 4 of this thread. The big visual difference between the ULEV engine is the exhaust manifold.

https://www.hondaaccordforum.com/for...5-p1739-50843/

 

Here is what I ended with. Took the new O2 (bosch) sensor back and got a Denso. Also took cat off. However every auto parts store around me has to order new one. So I gutted to cat and put it back on. Problems gone and haven't returned for 25 miles and 4 starts. Car runs great, but I think I have small exhaust leak where cat flanges connect. Sounds a little like a moped. However car runs smooth and has the power to pass without worrying. Thanks for advice and just wanted to leave followup. Thanks for you alls advice!

 

Will this year accord be okay to run without the inner parts in the cat. I know some people just straight pipe back to keep from spending money. Just wandering because I don't want to do any damage to anything. Thanks

 

Over the time it might begin throwing a CEL for cat going bad. Then you won't notice if it gets a new additional code for some other problem.