loss of power and it shuts off

when going down the road the engine begins to miss then when you come to a complete stop it will probably shut .  Wait a few minutes and try to crank and it may run ok for a little while but it may not.   It has lost power going down the interstate.  The check engine light has come on and we had it hooked up to a diagnostic piece of equipment and it tells me it is the coil pack.  Haven't changed it as of yet but want to try and get it fixed.  Have tried fuel cleaners but that is it.