i swapped motors in my 2002 mustang gt. The motor was out of a 2001 mustang gt. Whenever I start my car it will idle but it idles really rugh and then will die. Recently it won't even want to get going I will put it in gear and start going but then it just chugs and doesn't want to go anywhere. When I turn it off and start I it again it goes then starts doing the same thing. This only accurs sometimes. It will always idle bad but when I get going it will do fine until I stop again. Any idea of what is causing this please help!!!!!!