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Unread 03-20-2011, 10:57 AM   #1
whiteys_red_XJ
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what kind of spark plugs for my XJ

hi im planning to do a tune up on my 96 xj i will be running accel wires,cap,rotor,and coil. I had E3 before but the prongs all burnt of when i changed them i then put in champions in. and i was just wondering if the champs are the best for an xj with 179k on it any help is apricated thanks

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Unread 03-20-2011, 11:14 AM   #2
mtwask01
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Yes, definitely use the champion spark plugs type RC12LYC. These are the OEM spec spark plugs for your engine. I just changed mine from Autolite AP985s and noticed a much smoother idle. My idle no longer fluctuates up and down at stoplights. Make sure the gap is .035".
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Unread 03-20-2011, 11:23 AM   #3
VTEK1
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Quote:
Originally Posted by mtwask01
Yes, definitely use the champion spark plugs type RC12LYC. These are the OEM spec spark plugs for your engine. I just changed mine from Autolite AP985s and noticed a much smoother idle. My idle no longer fluctuates up and down at stoplights. Make sure the gap is .035".
I use Bosch platinum plus they last for a while and never had any issue with them. I have run them on my 99 since day one 91000-150000 miles. And napa wires
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Unread 03-20-2011, 11:36 AM   #4
mtwask01
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Originally Posted by VTEK1 View Post
I use Bosch platinum plus they last for a while and never had any issue with them. I have run them on my 99 since day one 91000-150000 miles. And napa wires
Is your Jeep one with the distributorless ignition, because I'm pretty sure those use different spark plugs.
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Unread 03-20-2011, 12:19 PM   #5
Dbiked
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Haha Just for ****s, i checked the gap of my old spark plugs, after doing a tune up on my jeep, The gap was .65 , almost double what they should have been haha
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Unread 03-20-2011, 01:02 PM   #6
VTEK1
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Quote:
Originally Posted by mtwask01

Is your Jeep one with the distributorless ignition, because I'm pretty sure those use different spark plugs.
No its got a distrubitor i just use those instead of champions. Nothing bad about champions however
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Unread 03-20-2011, 01:55 PM   #7
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I just put a set of autolite #985 spark plugs in my 98xj for cap and rotor I used the napa belden parts they have the brass contacts.
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Unread 03-20-2011, 02:04 PM   #8
BeachinXJ
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Quote:
Originally Posted by Dbiked View Post
Haha Just for ****s, i checked the gap of my old spark plugs, after doing a tune up on my jeep, The gap was .65 , almost double what they should have been haha

Stock is .035, so .65 would be way more than twice the factory gap.
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Unread 03-20-2011, 04:03 PM   #9
VTEK1
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Quote:
Originally Posted by BeachinXJ

Stock is .035, so .65 would be way more than twice the factory gap.
Lol i think the decimal place is a little off. Wish they would do that wirh my paycheck
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Unread 03-20-2011, 04:17 PM   #10
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From experiences of many on multiple forums....

84-99: Plain old champion copper plugs

00-01: NGK. The ignition on the 00-01 is different (coil pack) and NGK are a very good choice for these. Jeep started using NGK for their OEM plug on the 4.0 somewhere in this time frame, possibly 2002.

I love Bosch products, but because some (not all) have had mysterious misfires with them which have gone away when switching plug mfgs, I can't recommend them.
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Unread 03-20-2011, 04:43 PM   #11
VTEK1
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Originally Posted by tjwalker View Post

I love Bosch products, but because some (not all) have had mysterious misfires with them which have gone away when switching plug mfgs, I can't recommend them.
Interesting to note. I'll keep an eye out for this, never heard anything bad until now. Thanks.
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Unread 03-20-2011, 04:48 PM   #12
tjwalker
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Quote:
Originally Posted by VTEK1 View Post
Interesting to note. I'll keep an eye out for this, never heard anything bad until now. Thanks.
This Bosch plug miss is something that is very interesting indeed. I have just recently started collecting information on it and investigating it a bit. I absolutely love Bosch. I have their dishwasher, their power tools, their engine management sensors, the list goes on and on. Bosch has very good engineering.

The mechanism behind the 4.0 misfires is very unclear and what clouds this more, is that it absolutely does not happen to everyone, only to certain engines; the majority of Jeep 4.0 engines will probably work fine with them. Because of the complexity of trying to figure this out without a controlled large scale experiment, (my pole shed and checkbook aren't up to this!) the cause is unlikely to ever be understood by us end users.

But, because of the volume of threads about this, and the fix clearly being to switch plug mfgs, it is apparent that there is a connection here; this is not just one person thinking that their misfire was caused by their Bosch plugs. It's quite a few reported events.

The above is why I can't recommend them, but can make the recommendation of Champion for 84-99 4.0 engines and NGK for 00-01 4.0 engines. Never an issue with these plugs and these applications.
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Unread 03-24-2011, 06:06 PM   #13
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champion gold truck plug
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Unread 03-24-2011, 06:36 PM   #14
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Another vote for Champions...they're used factory, so that's good enough for me!
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Unread 03-24-2011, 08:24 PM   #15
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I installed those new E-3 plugs and they work great..
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