I have a 03 SPORT which I just go done doing my plugs on it !! My ? is why would someone gap the plugs at .070
instead of at the suggested .040 ? I hope with changing my plugs and putting them at the suggested gap will give me
lot better gas mileage . Right now I'm getting 16.6mpg . Hope you can explain this to me . Thanks Dave

The gap grows as the electrodes wear with use.

A larger gap will make the engine run too rich and a smaller gap will make the engine run too lean. Both instances will reduce your mileage. Just use a good quality spark plug and make sure the gap is .040-.045". I don't like those spark plugs that have 2 or 3 electrodes on them. I like using spark plugs brands like Bosch or NGK.

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2002 Jeep KJ Sport 3.7L 4x4

245/75-16 Mastercraft Courser HSX, 16x7 Cragar, 2" OME MD Lift, ARB Bumper
AEM Brute Force Cold Air Intake, Flowmaster Super 44 Muffler

Currently working on: Full service on transmission & bed-lining ARB bumper

viewtopic.php?f=43&t=84650

Don't flame me for being a newbie, but...

1) How do you set the gap of the spark plugs (will I need a shim of some sort, etc).
2) I am confused by the spark plug wires on the motor. They don't look like the ones I replaced on my Explorer ('92) years back. (I mean they look a lot narrower, and they are bundled with some other wires too..)

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'04 Renegade 4x4
L.O.S.T. #058466
Car Domain, Updated: 2/23/2009
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There are no plug wires like the old days . They have been replaced with computers and other stuff !!!.
I did my plugs last nite and it only took me about 1 hr. plus cleanup . I would make sure you move the coolant overflow tank out of the way. This will let you get the back 2 plugs on the left hand side . TAKE YOUR TIME on this and save some
money and do it yourself. Anyautoparts store will have a feeler gauge for thge plags for about $1.50 . If you still have the stock plugs in ,be carefull cuz they are very tight in there. You do not have to retightin them that tight . Gooodluck .
Thanks for you input on this .

I tried to do this and gave up I couldn't (didn't want to?) pull hard enough to get the clamp/hose to come off. Besides that I also needed a longer extension bar (10"?) than I had at the time. I wouldn't have been able to get at the plugs even if I got the tank off, so I went to Pep Boys and sheepishly asked to have them replace the passenger-side plugs ... boy, I got funny looks. At least I gapped my plugs already

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how much mileage did you have on this? they must make OEM plugs out of complete garbage for the gap to grow that big.

for new spark plugs anything from .025" to .045" will run fine, smaller will make the idle slightly rough and more will cause full-throttle problems and also large gaps are hard on the ignition system. look at autolite XPs, they are nice spark plugs and last longer than those japenese plugs do, as the autolites are double platinum and the imports are not, 1/2 the price too ($6 vs $12)

PN for autolite XP for the 2.4L is XP5263 (gap at .040") PN for the 3.7L is XP3923 (gap at .035"). you can buy them at advance auto parts or online at ROCKAUTO.com.

Two things.

I remove the tank from the firewall and stretch it up out of the way with the hoses attached. I do have some concern about having pulled that hose around like that a few times, so next time, I'll replace it.

Don't feel bad about taking those plugs in -- if you don't have the tools, you don't. I took my son's Camaro to the shop to have the power steering hose replaced. To reach it to get it off I would have needed the correct crowfoot flare nut wrench, and the ends are different sizes. Rather than struggle with it and/or get some tools I might never use again I had it done. Overall, would have been cheaper to have gotten the tools -- but Oh Well.

It sounds like you now have the extensions you need.

I used Bosch plats for the first plug change at 51k. I just did mine today after reading everyone else's experiences and I must say it was def not as hard as some would lead you to believe...my tips would be disassemble the whole intake down to the TB and pull that coolant bottle off and push to the side. Those coils come out EASY, much better than yankin on plug boots...

ALSO, I found that three of my crankcase hoses were dried and REALLY cracked...I got some bulk 19/32" heater hose and replaced the pieces...fit like a glove, no clamps. Something to look out for!!

JP