8 years old? Since you have replaced the parts Id go ahead and replace the rubbers. Hoses are cheap and sold by the foot at most auto stores.
Id get the ones for gasoline or fuel line and use hose clamps on the ends.
I doubt the gas cap is the issue, but what about the filler neck? I had one get loose from a tank and cause me to loose some gas at every fill up and from some sloshing around. You would need to look under the car or remove the fender liner on the side the fill up thingie is.
I had a 2010 honda insight and that was a random error I got often and I owned that car since new. I kept a scan gauge connected for other data and cleared that code every few months.