spark plug gap -
LinkBack Thread Tools
post #1 of 6 Old 07-12-2002, 10:59 PM Thread Starter
Registered User
Join Date: May 2002
Posts: 121
spark plug gap

I did a search to try to find what the gap of a spark plug in a 99 4.0 litre, had no luck maybe one of you could help.

desert sand 99 tj sport, 5spd, 4.56, arb front, f8.8 rear, custom bumpers, 1"bl+mml, warn m8000, 35 12.5 trxus
badams is offline  
Sponsored Links
post #2 of 6 Old 07-13-2002, 01:06 AM
Registered User
Quan's Avatar
Join Date: Mar 2002
Location: duhville
Posts: 1,098
sorry to intrude but i have a question about spark plug gaps too.. Is it true that you can gain some power by widening the gap on the plugs? I heard it somewhere on some post but i wanna know if its true.

There comes a time... In every mans life, when decisions... have... to be made. Whether to toil, to labor, or just plain piss your days away.

Green Jeep Club Member #15
My Jeep Made Me Broke Club Member #2

93 YJ I-6 w/ stuff

Keep the greasy side down

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Quan is offline  
post #3 of 6 Old 07-13-2002, 01:51 AM
Mark K
Registered User
Mark K's Avatar
Join Date: May 2002
Location: Central Arizona
Posts: 268
Did you try looking under the hood for the factory sticker? If it's still there and still readable it'll give ya the gap...
Mark K

Don't ask me! I just post what my dog [Emma] tells me to.

Member of:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Mark K is offline  
post #4 of 6 Old 07-13-2002, 07:59 AM
Registered User
Join Date: Jun 2002
Location: St. Louis, MO
Posts: 41
I know when I got my plugs from Napa, it actually had the gap printed on the recipt. I'm sure it is the same for most years, but my '97 FSM says a gap of 0.035" (0.89mm) for both the 4.0 and the 2.5l.

97 TJ Sport, Red, Too many mods to list, If you want to know just ask.
bonz44 is offline  
post #5 of 6 Old 07-18-2002, 09:11 AM
Sold my soul to JeepForum
FunkSkunk's Avatar
1992 YJ Wrangler 
Join Date: Mar 2002
Location: Marble, NC
Posts: 1,814
If you get the new BOSCH plugs you won't have to worry about the gap. Just get the double or the 4 prong ones and slap them baby's in. I got the doubles right now, feels no real noticeable difference. BUt you can't feel much of any performance gain with 33s and 3.07 gears!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
FunkSkunk is offline  
post #6 of 6 Old 07-20-2002, 08:59 AM
Registered User
rogncrys's Avatar
Join Date: Jan 2002
Location: vermont
Posts: 145
the gap is probably .035 for stock
you can open the gap up some, but may foul up and miss fire more often.
I put in a jacbs omni box, and that opens the gap up to .050, but put it a little closer to .045. and I have to change the plugs more often.

98 TJ and 02 Liberty
rogncrys 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

Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
who makes the best spark plug? Brendan Engines & Drivetrain 48 08-20-2013 11:15 AM
Spark Plug Question GADawgFan Engines & Drivetrain 2 06-10-2008 07:28 PM
spark plug trouble scotth Engines & Drivetrain 2 04-17-2007 10:08 PM
spark plug change 01jeepgrand Audio, CB & Ham Radios, GPS, & Electrical 3 08-22-2005 07:46 PM
Spark plug gapping 92cherokee Engines & Drivetrain 1 05-23-2002 09:32 AM

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