When starting my Expedition it idles at 500rpms.

When starting my Expedition it idles at 500rpms, running rough. I proceed to drive down the road and can smell a fuel smell in the driver compartment that never seems to go away. The miles per gallon on the dash has reduced to 11 mpg from 14 mpg however the dealer hooked it up to a computer and tells me I am getting 17 mpg and that the fuel injectors are not faulty. There are no engine codes appearing. When first noticing the problem, there was a code indicating a bad coil pack on cylinder 7. This was replaced along with all spark plugs. Code went away, but idle and smell persist. The dealer thought fuel was running down the tank neck creating the smell in the driver compartment and placed a hose clamp on the fuel neck/fill spout connection. Smell still there. The motor also has a ticking sound in it after it warms up that you can hear as it idles but less so while running. Dealer thinks that this may be a slight crack in a manifold. I believe these are two separate issues and unrelated. I have been to two dealers regarding these issues and neither ever agree on the solutions. Any help would be greatly appreciated.