2002 Dodge Intrepid iM having starting problems with my dod

My gf drives a 2002 dodge intrepid with a 2.7L engine. Occasionally when she goes to start it her car wont start. The engine turns over and everything but it will not start? We both want to get this fixed but we have no idea where it could be origination. It doesnt do it all the time only occasionally (like once or twice in a 2 week period) when this occures we have found the only thing to do is let it sit about ten minutes which can be very frustrating. But it usually starts up just like normal after ten minutes any help would be appreciated with this. Even slight possibilitiies of what our problem would be would help too. At least then I would have an idea of what to check and where to start thanks again