Porsche Cayenne (955) Spark Plug Replacement September 05 2025
Bad spark plugs can cause rough idling, intermittent misfires, and poor fuel economy. We replaced our spark plugs on our Cayenne and experienced a smoother idle and restored fuel economy. It's not an overly difficult job. It took us about 2 hours, while documenting the process.
If your Cayenne is equipped with air suspension, lowering it to loading height can make the job easier, as you can reach easier. The first step was to remove the beauty covers, starting with the side covers and ending with the aft cover. The front covers do not need to be removed. The covers are held in with quarter-turn fasteners, and one screw.
The quarter-turn fasteners can be removed using a coin. A United States nickel works well.
On the passenger side, there is also a Torx screw that needs to be removed.
There are two air pumps that need to be unmounted so that they can move out of the way of the engine beauty covers. Remove the three T30 bolts on each of the air pump. It is not necessary to disconnect any additional items from the air pump.
We turned our attention to removing the torque arm, starting by loosening the outboard bolt.
On the inboard side of the torque arm, we loosened and removed the bolt and nut. It is a 16mm nut and a M12 triple square bolt. With this bolt and nut out, you can swing the torque arm up and out of the way, or just remove it completely.
We then removed the engine beauty covers by removing the T30 bolts on each beauty cover. Be careful not to drop these, or they will likely end up on your underbody splash shield and you will have to remove the underbody splash panel to retrieve it.
The aft bolt on the passenger side may need a smaller tool to access it.
With the bolts removed, pull the beauty covers towards the intake runners and wiggle them out. Push the air pumps out of the way as necessary.
Loosen the E12 (external Torx) bolts to the bracket shown above. Note that the inboard and outboard bolt lengths are different, so don't mix them up. We just left the bracket in position and lifted it up when we needed to access the coil pack underneath it.
We then removed the bolts to the coil packs. The most difficult to access one is shown above. It is an E12 (external Torx) bolt.
We removed the connector to the coil packs. Press down on the tab and wiggle the connector off. With the connector removed, we lifted the coil pack up and out of the spark plug hole. Twisting the coil pack back and forth helped loosen up the stuck coil packs. Inspect each coil pack for cracks in the body, as this is a fairly common issue. You may consider replacing your coil packs while you are in here. Bad coil packs will also present as misfires, rough idling and poor fuel economy.
We removed the spark plugs with a spark plug socket.
One of the old spark plugs.
The new spark plug. We used Bosch 7413 plugs. This particular spark plug does not need to be gapped. We installed our plugs dry without any anti-seize.
It is very important to use a torque wrench to reinstall the spark plugs. The torque specification is 22 foot-pounds. Reassembly is the reverse of disassembly. There are a few items to note.
- Some of our coil packs had to be gently pried into position with a pry bar so that the mounting hole would line up with the threaded hole in the head of the engine. You can cross-thread the bolt if the holes are not aligned and you are not careful.
- You may choose to function test the spark plugs after installing the spark plugs, coil packs and torque arm. If there are any issues, it will be easier to address before the engine bay is fully reassembled.
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