03 GT stalls out when clutch is pushed in
A little background to the vehicle. I have an 03 Mustang GT 5 speed; so far I haven't done much too it. The previous owner had some bolt-ons done but that's pretty much it. I'm running BBK shorty headers, and a pro-m cold air intake system. I had a leak in the intake manifold that was causing a misfire and since has been replaced and no more leak or misfire.
The issue I'm at now is when coming off the highway I press the clutch in and the idle drops to around 200rpm and sometimes the car stalls out. Now my idle is pretty low to begin with anywhere between 500-700 rpm with a little sputter here and there. I have gone through with MAF sensor cleaner cleaned it, cleaned the filter, used throttle body cleaner and cleaned the throttle body when I had it unbolted and still nothing seems to solve the issue. I have tested for vacuum leaks and non are present. I know I have a leak in my driver side header due to a bad gasket but that wouldn't cause the car to stall out. I have pink injectors (21lbs I believe) I do not know what my MAF is. Has anyone faced this issue or have any idea what to do?