How To Change Spark Plugs on 4.7 V8 FlexFuel

I haven't seen a specific thread on how to change the plugs on the 4.7. It's not a very hard task by any means. I'll explain it the best I can here on this Thread.

Step 1: Buy replacement plugs. I bought mine at O'Rileys. They are Bosch Platinums. Cost: 2.99 each.

Step 2: You must remove the plastic intake cover shown in picture.

https://theultimatejeep.com/images/i...IMG_2107-1.jpg

There are two bolts to remove. One on the right and one on the left. You can see the driver side bolt in the following picture right next to the first spark plug coil.

https://theultimatejeep.com/images/i...IMG_2104-1.jpg

There is one identical to this on the other side underneath the air intake hose. Go ahead and take the hose off first since the bolt is underneath and difficult to get to when it is still attached. The only thing holding this on is the pipe clamp. Just loosen the clamp with a flat head screwdriver and pull the hose off and push it aside. Now remove the MAF sensor plug right where the hose connects to the plastic cover. You can now easily remove the bolt beneath where the hose was.

There is one last item before removing the plastic cover. On the rear of the cover there is another air pipe with an identical pipe clamp holding it on. It's hard to see from the front. Once the clamp is loosened you can pull the plastic box forward and up slightly and it should pop off easily.


Step 3: Now it's time to remove the plugs and replace. You can see them in the second picture very well. They have a plug on top that must be unplugged. Now use a socket wrench and remove the tiny nut holding each of them down. They are now loose and you can pull upward and wiggle a bit. They should pop off without too much effort. To remove the plug you need a Spark Plug socket that fits the same ones you bought to replace the old ones. Connect that to an extention and a socket wrench. Sometimes you will need to slide the socket and extention into the hole without the wrench attached and then attach it once it is gripping the spark plug due to space requirements. Gently loosen the plug. It can be a little tight be be sure not to pull sideways on the socket wrench so that you do not break off the plug.

BE SURE THAT WHILE THE SPARK PLUG IS OUT OF THE ENGINE NOTHING DROPS INTO THE HOLE WHERE THE PLUG FITS.

Replace the old plug with the new one. This is how my plugs looked when I just replaced them. I believe these are the original plugs and i only have 50k miles on the engine. They were pretty worn down.

https://theultimatejeep.com/images/i...IMG_2106-1.jpg

Replace the coil pack onto the plug and tighten the nut back onto the stud. Remember to plug the plug wiring harness back into the Coil as well.

Repeat for all eight plugs. The back passenger side is a tighter fit but still not much of a problem.

Step 4: Replace the plastic cover. Tighten both hose clamps and bolts.

Step 5: Replace the MAF sensor plug.

Step 6: Crank your engine and enjoy a smoother idle.

I noticed my XK was idling rougher than I'd like and this prompted me to replace the plugs. It was well worth it. It is much smoother on the idle and could possibly give me a MPG hopefully.

Hope this thread helps.