sebring convertible

I have a 96 sebring convertible the car starts up fine, I have changed the fuel pump the fuel filter, spark plugs, and many other things. My problem is that when I am driving the car it will just shut down it doesn't do this all the time there are times when it will run just fine. There are other times when I am just waiting at a light and then it will spurter but it won't shut down, then as I get to other light and wait it will shut down. I don't know if its the fuel pressure regulator or a fuel injector how can i test these, and what may also be causing these problems

loose or corroded ground somewhere.