I'm not sure if this is the right forum for this but...
I got a misfire code on cyl 4 and sometimes cyl 1 lately after a flat battery jump start. I've swapped the coils and reset the CEL. The CEL comes back on after a day, sometimes after a week or so.
I'm not sure if the jump start damaged the coil or sensors or connectors to the ECU. It could also be clogged injectors, etc by coincidence.
Is there usually a delay for the CEL to turn on for a misfire code? P0304. I've brought it to Honda to check it but they just reset the CEL after spark plug and coil swap too. The light turned back on after 2 weeks. Same code. Sometimes I get different pending codes too. Help?

 

Hey Jon, I'd post this question here, in Under the Hood!

 

Kinda late to this show but...

When I had my first AP1, it took up to 40km for the CEL to turn on solid, even though the engine was running rough at idle.

If you have an obdii reader, you will likely be able to see a pending misfire code much faster. The freeze frame data and the fuel trim numbers will also offer clues to what's causing the issue.

Which Honda dealer is resetting the ECU? My first AP1 came with 2 years of service history from a local Honda dealer. The previous owner paid the dealer over and over again to troubleshoot misfire issues, but all they ever did was repeatedly charge the guy $80ish for resetting the codes.

 

This is a good question! Good dealer to stay away from!