Spark plug Recommendations - Page 2 -
LinkBack Thread Tools
post #16 of 19 Old 05-04-2014, 10:51 PM
Registered User
2000 WJ 
Join Date: Apr 2014
Location: St. Petersburg
Posts: 8
I agree with ChrisHagar. The 4.0 recommends Champion RC12ECC coppers plugs gapped at .035. My 2000 WJ 4.0 came with Autolite platinums. I switched them out with the Champions and my engine runs fantastic. Go copper!

PJWJ is offline  
Sponsored Links
post #17 of 19 Old 05-05-2014, 08:53 AM
Registered User
1999 WJ 
Join Date: Aug 2011
Location: Bethlehem
Posts: 308
+1 on that. champion copper.

1999 Jeep WJ, 78,072 miles new adco sway bar in rear. new rotors hubs and caliphers, new cv axles up front, Repainted-all black. steering system better stabilizer new tie rods and tubes. New shocks.
Amadauss is offline  
post #18 of 19 Old 05-08-2014, 12:21 PM
Registered User
2004 WJ 
Join Date: Sep 2013
Location: Los Angeles
Posts: 56
The decal in my '04 4.0 specs NGK ZFR5N; they work great!
hvadreamn is offline  
post #19 of 19 Old 05-08-2014, 12:35 PM
Registered User
2004 WJ 
Join Date: Dec 2009
Location: Kansas
Posts: 142
Originally Posted by 86cj74.2L View Post
The coil on plug found in the 4.0 is more sensitive to plug type since the spark travels out one plug and in the other.
Don't know who told you that, but they lied to you.
All spark plugs, in all gas engines, fire to ground....not to another spark plug.

Last edited by mudpack; 05-08-2014 at 02:38 PM.
mudpack is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome