Compared to the vehicles I grew up with, the amount of ignition maintenance that is required on today's vehicles is almost non-existent in comparison to the engines from the 1960's. Setting the points, making sure the condenser was good, and chalking up the timing marks so you could see them in the timing light was a very common weekend task. With today's engine computer mostly running the show, we are mostly left with throwing in some spark plugs every now and then and maybe even a rotor cap with wires once in a while. I don't remember when I last used a timing light....oh well, engine computers are our friends (just keep telling yourself that).
The items required for a typical spark plug change are pretty straight forward. You'll need a 6 pack of new spark plugs (or a 4 pack for you cylinder challenged owners), a 5/8" spark plug socket, a 3/8" ratchet and extension, and a wire feeler gauge.
I used to use the Champion 4412 truck plug but they stopped making it. A good plug available now, for the 4.0L engine, is the Champion 3034. They cost a bit more but will last longer.
If you have the newer 4.0L engine without a distributor, they can be picky as to what plug they prefer. There are several good plugs for your coil-pack engine which include the Autolite APP985 and Champion 7034 (both are double-tipped platinums) or Autolite XP985 (Iridium). Avoid installing any single-tipped platinum plugs if your TJ has coil-packs in its ignition system.
One thing you might find handy for this project, and for just
about any other one for that matter, is a set of "wobble" extensions
for your ratchet. I used one about 12" long for all of the spark
plugs except the one in the back cylinder (against the fire wall). That
one got the 6" version. The "wobble" extension allows the
socket to wobble back and forth a bit, as can be seen in the above photo....note
how the socket and extension are not aligned with each other. By doing
this, it eliminates the requirement of having everything lined up nice and
straight. This can be a blessing in a cramped engine compartment where you
can't always get a straight on shot at the spark plug.
The one thing I have constantly been told, ever since buying my TJ, is that it is nearly impossible to get the #1 plug wire off of the spark plug (assuming you have an A/C compressor under the hood). I was ready for this one, having heard horror stories about peeled knuckles, bloody fingers, and even worse things happening to those who braved ol' #1. Well, I'm here to tell you that a medium sized pair of common pliers, carefully grasping the spark plug boot, will remove it in about 5 seconds with minimal effort. I'm still not sure what all the hoo-haa is about, but I sure spanked that boot, no doubt about it!
There you go....living proof that it can be done with just a simple pair of pliers. Since you can't see the back of my hand, you'll have to trust me when I say that the skin on my knuckles are still intact.
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