You might have a fuel line leak somewhere in the engine bay compartment or nearby. It will enter the fresh air inlet duct that is atop the hood, do you smell a fuel leak anywhere under the hood area, especially on cold startups? What happens is sometimes a fuel leak will disappear with the warming up of lines and seals because heat obviously allows for expansion, so they swell sort of speak and seal better off as the car is driven or warmed up.

Haven't seen it happen on an accord, only a Nissan Maxima, but anything is obviously possible.