For the fuel filler, jack the car up and remove the right rear tire. You can see the filler tube under a plastic cover. These tubes rot and leak often, may be collapsed from road debris or a blow out. Easily replaced. , you can get one from local junk yard. Pay special attention to the configuration, i.e. how the vent hose attaches. The junk yard will have a couple of different configurations, only one will fit.