[91mustangowner]

i'll agree with 84LX. it is deffinatly your coil packs......i have a 91 2.3 with the duel fire system so i got two coil packs so i got 8 sparks plugs.... 2 plugs per cylinder one other thing you might try replacing.....and you can do this yourself.......is the O2 sensor....even after i replaced the coil packs it still gave me little sputtering and shaking fits until i got a new oxygen sensor....been running good ever since