A carefuly placed defouler can help with this. RV6 typically includes one. I've seen RV6 catless downpipes go thousands of miles without a CEL thanks to the defouler.
The emissions system error results in a check engine light. You can use a tune to hide the check engine light in some cases but...
Make sure the axle is correctly seated, if not, you will not be able to get close enough to reattach it there. It comes out pretty easily during a suspension upgrade such as this.
You can try swapping the coil pack to another cylinder and seeing if the misfire moves as well.
As others have indicated, fuel injectors are unfortunately a common point of failure for this platform.
For what it's worth the muffler is there to make it quiet. The resonator is good for getting rid of drone and other harsh sounds. It will also decrease volume a bit.
Are you using NGK plus and an OEM coil pack?
Also: https://www.civicx.com/forum/threads/misfires-and-you-diagnosing-misfires-on-a-2016-2021-honda-civic-1-5t.71259/
That's your inspection cover for the clutch. You can take it off and take a look inside. I'm guessing that you will find it to be dry in there and that your leak is coming from somewhere else, but it won't hurt to take look.
I may or may not have traded a car back to Honda like that. I didn't have a replacement fuel line at the time so I just let them have the flex fuel sensor. :lol:
As noted above he is prioritizing some family issues at the moment. I do not want to share all of his personal business here but here is the end of said post:
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