2002 Nissan Altima

2002 Nissan Altima 2.5, Automatic, 82000 Miles. When I go to start it it won't turn over right away, sometimes it takes what seems like forever and other times only a few seconds. Once it does start it smells like gas. It idles rough at first but once you get going it runs fine. Once you get to a stop it idles rough again and seems like it wants to stall. Is this a fuel problem or something more serious?
May 20, 2007.

Check your fuel pump for noise. It is located by your fuel tank, just listen for hum or whistle. Also, replace your spark plugs and wires, make sure to get propper gapping on the plugs. If still running poor, replace the cap and clean or replace the injectors.

May 22, 2007.