2000 Jeep Wrangler Fule Pump or Injectors?

Recently my Jeep has started taking considerably longer to start, it turns over for 15 seconds or more. When it finally starts it chugs and runs rough for a minute, almost as if it isn't getting enough fuel. Upon starting there is a smell of gas inside the cab. There are no visible leaks on the gound and there is no hesitstion of power at any speed. A friend of mine stated he thought it may be a fuel pump or an injector. How do I find out for sure?