I have a 2006 Ford Mustang GT. And its starts great but when I put it in drive it wont go nor will it go in reverse.

Your car has an "accelerator position sensor" which sends an electronic signal to the engine when you hit the gas. This part can make the motor run erratically as it begins to fail. But before replacing this $125 part, vacuum up the dirt around the gas pedal and clean the electrical connector carefully and see if that fixes the problem. If things still aren't right, you should read the codes again or have a mechanic look at it to be sure that's the problem before buying a part that can not be returned for refund. My girlfriend had a Lincoln MKZ that did the same thing and probably uses that same Ford part. Moisture and dirt kills them. I hope this helps.