If you've got a 97 then I can't say for sure what extended warranties apply, but I'd imagine it's the same as the 98-01 V6 Accords. Honda extended the warranty range to 80,000 miles for faulty EGR systems. This covers the codes P0401 (insufficient EGR flow) and P1491 (insufficient EGR lift). Honda makes an EGR pipe kit that fixes the problem - basically they bore out the EGR port and install a pipe in it. A Honda dealership should charge around $125 (can't remember the exact number) for the part and no more than a few hours of labor.

The check engine light on my 01 V6 started coming on when the car had 82k miles and it turned out that insufficient EGR flow was the problem. One Honda dealership gave me an estimate of $350 for the labor which I thought was too steep. I took it to another dealership and they estimated $200 for labor so I took it there (which was just today actually.) Even though I was just above the 80k extended coverage, they fixed it under warranty before I even got a chance to ask them to, so I left without spending a cent. You may be able to get the same done with yours, but 125k might be too high. Never hurts though.