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Discussion Starter #1
Ok, I know that this subject has been beaten to death but I'm still having trouble figuring out what to do with the spark plugs in my '08 4.7 xk

Has anyone changed their plugs yet? Keep in mind this is the new engine that requires the 16 plugs. OEM says the top row is Bosch Nickel Yttrium and the bottom row is Bosch Iridium. When looking up what sparkplugs.com recommends It doesn't even show the Iridium's.

My questions are:

-Should I stick to OEM or would the Bosch Platinum's listed on sparkplugs.com be ok to use?
-Has anyone changed theirs before and have any issues?
-They recommend changing the top row at 30k and the bottom at 60k. I am at 36k and haven't changed them yet. Should I not worry about the bottom row and just focus on the top for now?

The dealer charges $500 to do the job, and since I never had to change 2 spark plugs per cylinder before, I want to make sure I do it right!
 

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Discussion Starter #2
...Plus where can you find a thin-wall spark plug socket. The auto parts stores around here don't carry them and apparently its required to remove these plugs.
 

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Just do the top for now.
Those Iridiums will be fine far longer than 60k.
I'm actually surprised they are calling for their replacement at that low a mileage.
Usually, Iridiums are rated 100k.
You might want to contact Bosch sparkplugs.
As I read their application page, it appears you can use the same plug top and bottom as they are not calling for different numbers.
It appears to me you currently have Platinum plus #4030 plug#FR8LPX+ installed across the top and Platinum IR (Iridium) Fusion #4508 plug#FGR8LQI0 on the sides.
The fact they are both F,LETTER CODE,8 indicates they are the same reach, same projection and same heat range.
So, it seems you could run the 4508's across the top with confidence.
I'll bet Jeep used the cheezy plug up top to save money.

My thoughts, opinions,
Rob

PS,
Chase down a tool truck....Snap On, Cornwell, or whomever services your dealer mechanic tool needs for a thinwall.
 
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