I have a 2003 GT and recently the car began to have trouble starting and soon when it did start it would run like it had a misfire and then quit. I replaced my fuel filter and now it will stay running but it's still very odd the way it idles. Starts fine and starts at about 2000 rpms then comes down to about 700 rpms and barely stays running and still chugs like it has a misfire. So my question is, is my fuel pump on the way out or could this be something else. Thanks for any and all help. It's much appreciated.