i have a 04 mustang cobra it has the basic bolt on like superchager pulley mas air flow exhause chip. i bought it bout month ago it came with a racing c4 trans i never had a problem but when i put the 6 speed back in i m now geting lean codes does ne one kno what could be causing this. and one more ques i have to drive it everyday i have an appointment in 2 weeks to get it tuned right. from it running lean can it do ne internal damage and if i baby it can i still drive it everyday.

 

Yea the guy who swapped the tranny didn't set it up correctly..