ok so heres the beginning of the story.. I installed a pair fo bbk long tube headers and a high flow catted h pipe.. I wanted a louder sound so I put on a off road h pipe.. Ever since then my car has been trowing a lean code... It stutters too a lot around 1000 to 1500 rpms in every gear. I cahbged the throttle posiyion snsor with no gain or results.. So I question is y would it do this considering it didn't start till I put on off road h pipe. Is it too high flow maybe no back pressure or am I just and odd mustang that's acting funny.. Also do I have to have a tune in order to run this set up.. It's bothering me becauuse I've lost performance ever since installing my lt headers on.. I'm debating replace ing back to stock..