spark problem on 1-4

i have a 93 lumina 3.1L. i dont have spark coming off my 1-4 coil. i have spark sometimes and sometimes i dont. i replaced the coil and still the same thing. i was thinking that it my be the ignition module or the crank sensor. before i start ripping into it, i was hoping to get some opinions.

Your ignition module is bad. If it were a crank sensor issue, you'd either have no spark at all, or the no fire situation would move from coil to coil.

i will give that a try. thanks for the help.