It's the crank sensor!
Join Date: Nov 2007
Location: Central Minnesota
Your best bet would be to get the actual codes and post here for comment.
Don't replace that coil rail just yet......as Tim mentions, it generally is not replaced as a matter of course unless other things have been eliminated.
A new set of plugs should absolutely be installed (champions) as one of the first things to try. Not that it couldn't be the coil rail but basic stuff first.
Posting codes and replacing plugs would be a good start to a methodical process of elimination here....
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!