I have an 06 EX V6 and recently changed the OEM plugs with a set of Bosch Platinum +4 plugs and after doing so my average mileage went down from 25.6 to 24.3. This is after running several thousand miles without resetting since I reset after the plug change. I notice I have to fill up more. Very weird behavior...I had expected to maybe do a little better in mileage, not lose mileage. Should I have disconnected the battery to reset the computer? Are there any other ideas on what may have happened here?

 

You are lucky those plugs didn't kill your ignition coils. Hondas should only use Denso or NGK plugs. Bosch isn't good for Hondas because the resistance is not correct and this is likely causing an inferior spark leading to your loss in MPG.

Best bet, get a set of NGK plats

 

Thanks for replying with the useful information. I have used Bosch Platinum +4 for years so when I saw them pop up as a replacement plug for the Accord, I instinctively chose them. Now I am wanting to go back to the OEM plugs. Which one should I choose, the Denso or the NGK?

 

I would go with denso, just because they are a little cheaper and theres a slight different in performance better...the ngk is propably harder to find and usually more expensive.