You Will Need:

(DO NOT GET ANY OTHER TYPE OF PLUGS...THE MANUFACTURE SPECIFIED PLUG IS THE BEST FOR THIS ENGINE. IF YOU DON'T BELIEVE ME, SEARCH THE INTERNET AND FIND OUT FOR YOURSELF....or save your time and believe me because I did the research for about an hour before I purchased the new plugs)

Step 1:

Disconnect the negative terminal of the battery

Step 2:

Disconnect the air hose, which runs from the air box to the resonator box.

(Loosen the 2 hose clamps and remove the hose)

Step 3:

Remove the resonator box.

(2-10mm Screws and Hose Clamp On Throttle Body)

The 4.7 liter V8 engine does not use spark plug wires. The spark plugs get their spark from a coil-on-plug setup. These coil packs usually last a long time, and should not need to be replaced routinely.

Step 4:

Disconnect the wire from the coil pack and remove the nut, which secures the coil pack to the engine

(1-10mm Nut)

Step 5:

Pull the coil pack straight up to remove it. If you are unable to remove the coil pack, use a hammer for leverage.

Place the hammer as shown and support the coil pack with your hand where the wires connect. Pry the hammer upward as you push inward where the wires connect to the coil pack. The coil pack should then pop right out.

Here is a picture of the coil pack removed. Clean off the dust and dirt before you reinsert it into the engine.

DO NOT lose the blue gasket which surrounds the coil pack towards the bottom.

Step 6:

Remove the old spark plugs using a socket wrench, 3" extension, 1" extension, and 5/8" spark plug socket. The plugs may be in tight, but use some muscle and they will come out.

THIS PLUG IS BEAT! Although the electrode is worn down pretty far, the coloring of the insulator reveals that the engine is running fine (not rich nor lean and there are no oil deposits).

If your plugs resemble this, they should be replaced with the same kind of plugs (which is what I ordered).

The new plugs are already gapped correctly. Notice the difference between the gaps of the picture above and this picture.

Can't wait to get these in and go for a test drive !

Step 7:

Insert a new plug using the socket wrench, 3" extension, 1" extension, and 5/8" socket. Hand tighten and first and then tighten about 1/4 turn with the socket wrench.

DO NOT USE any thread sealer or anti-seize on the new plugs.

(Use the regular 5/8" socket to install the plugs INSTEAD of the 5/8" spark plug socket in order to easily retrieve the socket from the engine)

Step 8:

Insert the coil pack

Install the nut onto the coil pack

Connect the wire to the coil pack

Step 9:

Remove the throttle body to easily access the plugs towards the back of the engine.

Disconnect the wires for the IAC sensor and throttle position sensor. Remove the 8mm screws, which hold the throttle body on. Disconnect the throttle wires.

(3-8mm screws)

Step 10:

While the throttle body is off, you might as well clean it.

I did not use any chemicals to clean mine. A few paper towels and 5-10 minutes should do it.

Step 11:

The IAC (Intake Air Control) sensor (on the left) can be removed to clean the inside a bit better.

It can be removed by using a TORX screw bit. Be sure to reinstall it securely.

REPEAT STEPS 4 THRU 8 TO CHANGE THE REST OF THE PLUGS

The plugs towards the back can be tough to get to....but it can be done.

(You may want to substitute a crowbar for the hammer in Step 5)

The 3" + 1" extension + 5/8" socket will fit to get to the plug. Add the socket wrench when the extensions and socket are on the plug.

Step 12:

After all of the spark plugs are changed, reinstall the throttle body, air box resonator, and air hose.

Step 13:

Check to make sure that all sensors are connected

Step 14:

Re-Connect the negative battery terminal

Step 15:

Fire it up and enjoy!

FAQ:

Visitors to this site have searched to ask if this engine would run on only 7 cylinders. Theoretical, the engine probably would run on 7 spark plugs, but the ECU would throw a code and the Check Engine light would come on. After a scan of the OBDII system. The code should be defined. The code would probably note that the coil pack is bad. The reason that I changed my plugs is that I noticed a slight misfire every now and again while doing about 80 mph on the highway (according to the picture on step 6, I could see why one of the cylinders may have been skipping a beat).

*A friend of mine thought he would be a smart-ass, while we were drinking one night, and removed two coilpack wires and some other sensor. The Jeep actually did start and the engine sounded like it wasn't running too rough. However,the Check Engine light did come on. After the wires were replaced the Check Engine light went off after the next time I started the engine.