stutter

i have a 88 mustang 5.0 HO speed density no mass air with bout 38,000 miles ive done some modifications to car and dont know why it stutters.First of all it doesn always stutter it seems to be only when i give it mid throttle or when i first start to go the motor stutters, it wont stutter if i punch it,It goes away but if i baby it it will stutter? sometimes the stutter wont go away once it starts stutterin unless i punch it? the mods i have done are underdrive pulleys,full racing ignition by MSD(witch i was told was the problem,not the MSD itself but my ignition system cause i was havin trouble before it was installed) Also have a cold air intake (BBK),Hedman headers with stright pipe exaust and flowmasters(no catalystic converters)now i was told it is either fuel or ignition, I changed the whole ignition and fuel pressure is good any suggestions i love this car and dont want to get rid of it over minor issues i just cant figure it out please help if you have any suggetions thank you.[img:71788d8664]http://www.2carpros.com/forum/automotive_pictures/91923_100_0162_2.jpg[/img:71788d8664]