Man, I just posted something about this. It's not the EGR...

The EVAP system on 6th-gen Accords is mostly down under the car, about underneath the left-rear seat. There's a charcoal canister, a 'Vent-Shut valve' (gee, how bout that), and a small filter. It's not too difficult to replace, but kinda awkward without much room for your hands & tools.

If your mechanic hasn't already gone thru checking the different parts of that system, the check-engine light won't tell him which part of that system is bad.

Check this out...
https://www.honda-acura.net/forums/s...03#post1486403