XJ Starter/Ignition Please help

[CherokeeChieftan]

Once about every 10 times I start my Jeep it sputters really bad. My check engine light is on and when I took it to Advance Auto they told me it was a misfire on the 3rd cylinder. I changed all my spark plugs and it is still happening. A guy told me it was either the ignition coil or the coil pack. I can't remember which one he said it was. Can anyone help me diagnose the problem?
2001 Jeep XJ
Engine: 4.0
Thanks

 

[jeepguy242]

your jeep has packs that sit on a rail, its gonna be about 100$ either way as you need to replace them as a unit.

 

[CherokeeChieftan]

Are they both easy to install? The coil pack is the long black unit that is right above the spark plugs right?

 

[Jody Treadway]

Also there have been a lot of carbon buildup issues on the exhaust valves causing this as well. Also the number 3 injector can get heat soaked and cause a miss.

May wanna get it checked out before ya throw parts at it.