Hi everyone i have a 2001 mustang gt 5 speed that i recently installed MHS stage 3 heads, MHS 2.5 N/A cams, CAI, throttle body, Plenum, Injecters, and 255 Walboro fuel pump. Also have other basic mods such as coil packs, long tube headers, catless h pipe, and custom catback. The car ran on the stock tune but sputtered at high rpm's and would not idle after the install. I recently took the vehicle to a local tuner to get the car dyno tuned. After the dyno tune the car ran like a champ. I did not drive the car for over 5 weeks and then when i did the car threw a whole list of about 10 dtc codes and was running terrible. I set the car back to stock with my sct tuner and reset the computer on the car. I then loaded the tuners tune back on the car and it ran good again. Now no matter what i do the car is tempermental. The car will run perfectly fine sometimes when i start it and other times the rpm's hang a little high at idle and the car will sputter to about 1800 rpms. It will usually continue to do this throughout the day and sometimes downloading from tuners tune to stock tune and then back to tuners tune will fix the problems but other times not. There might be no way to answer this question because of it could be so many things but have got some great info off this site and thought i would ask. Is it the bigger cams making it sputter until that rpm range and idle different everytime? Is there a possibility it is a bad tune that i should take back to the shop. I have not taken it back because its 80 miles away and very expensive to get work done there. Could it maybe be a fuel pump or injector problem? i just dont see it that way because after it gets passed those rpms it runs great. Thank you for any help in advance