I've just replaced mine this past winter. Was getting cylinder misfiring on #5. So I replaced coil rail and plugs now runs like a champ bought coil rail from advanced auto parts was like 130. 2002 Sahara.
Sorry I haven't been on here for a while. Injectors r good as well as 2 dif sets of plugs. I actually had a local shop w a very good serv/reputation look at n they couldn't figure it out. It ate at the owner so much he had me bring it back and they checked everything that they could for free. Their best guess was the coil rail which is one of the issues that always comes up w the research I've done on here and google.