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saf98tj 08-11-2012 02:26 PM

Spark plugs - should I change them
Hi everyone
I recently purchased a 98 TJ 4.0. I am going through all the regular maintenance items so I can establish a basis for scheduled maintenance which i plan to do myself. I pulled one of the plugs to check condition and found e3 plugs installed. I don't know anything about the plugs and there are mixed reviews on this message board. I have no idea when they were installed and I have 120k miles. The question is should I change them out? The engine runs fine. However the service manual recommends changing at 120k. Any thoughts?

Thanks Scott

Notoriously_rob 08-11-2012 02:28 PM

Are they burnt - if not i wouldnt- e3 are really good plugs

Jerry Bransford 08-11-2012 02:30 PM

E3 plugs are a modern day version of snake-oil that is little more than shoddily made junk. E3's claims of better mpg & HP are only accurate when compared against spark plugs that are completely worn out... something they don't mention in their ads.

For your '98 4.0L engine, any of the three following very high quality plugs would be excellent choices... Autolite AP-985, Champion 3034, or the latest technology iridium tipped XP-985 which would likely be the last plug your engine will ever need. The first two plugs are platinum tipped and will perform well for 100K miles.

saf98tj 08-11-2012 02:49 PM

Wow thanks for the quick responses guys. I only checked one so far and it isn't burned. It looked fine. I haven't pulled the others yet as I didn't want to spend the time if I am going to change them. The wires look pretty new also. The PO who only had the Jeep for 10k miles didn't change them so it had to be the owner before who had the vehicle for most of its life.

Jerry I will take your advice on the plugs going forward. Would you bother changing them now if the engine is performing fine?

Jerry Bransford 08-11-2012 02:51 PM

If the engine is running fine, there is real no need to swap them yet. Your first post didn't include that they appear to be ok. Just make sure not to use more E3s lol. :)

saf98tj 08-11-2012 02:57 PM

I will check a few other just to see. No e3s in my future! Thanks for the advice. I have a lot to learn :-)

saf98tj 02-14-2013 09:58 PM

Just an update. My engine started sputtering and threw a p0302 code (cylinder 2 misfire). After some troubleshooting I determined that it was a bad plug. Now have a set of champions installed!

Gixxer86g 02-15-2013 05:07 AM

Get rid of that e3 crap. Put in Champs, Autolites, NGK, Denso. :thumb:

saf98tj 02-15-2013 05:39 AM


Originally Posted by Gixxer86g
Get rid of that e3 crap. Put in Champs, Autolites, NGK, Denso. :thumb:


Patrick H 02-15-2013 06:51 AM

I'm somewhat surprised you made it that long before one of the E3's crapped..;)

saf98tj 02-15-2013 11:20 AM


Originally Posted by Patrick H
I'm somewhat surprised you made it that long before one of the E3's crapped..;)

Probably because I have maybe put <1000 miles since my original post!

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