It's automatic but I have to start it all the way in first and leave slowly like it's a manual otherwise it stalls for no reason it's like having the three stooges ( ) try and tell me how to drive but for how much I bought it for I can fix it hopefully

 

First thing to do is pull any stored codes in the ecm. http://dfwmustangs.net/forums/showthread.php?t=7908

next step is determine if egr is sticking open, you can pull off the egr valve and clean it. I suggest eliminating it temporarily by putting a block plate in its place. Sounds like egr is stuck open. How does it idle?

Clean the MAF with some special spray for MAF meters you can get at autozone.

Look for vacuum leaks.

Check/test throttle position sensor