Good info, I usually replace mine every 25k ish, usually just for something to do though. Same with oil changes, I do it every 3kish just because..

 

Coppers dont wear out after 30k. At least the motorcrafts dont. My father changes his plugs every 30k and always has. When I pulled them out they were fine and the gap was only .002 bigger. I put them in a buddies mustang. He pulled them out a few months ago. At that point they had 80k on them. The gap had opened .002 again but they were still in great shape. . He put them away as emergency backups. The motorcraft coppers will easily go 100k in a normal daily driver.

 

A lot of info on that thread, and they beat the dead horse. I do also understand why I would use the cheaper one (run truck hard and change often) vs Plats (run less hard, and change less often). Since I run my truck as a hauler, and do almost no daily driving, copper.

Also it appears that the heat issues are the reason all the XJ people love the copper. They get dirty either way, so go cheap and change often.

 

It has better fitment than other rotors and the materials are better.

 

Pulled MC single plats from our 95 4.9 after 30k, it was starting up a little harder but ran fine. This same truck fouled MC coppers in less than 10k.

 

That truck has issues.

 

Indeed it does, but the teenagers drive it everyday and have for the last four years. I keep waiting for it to give up on us, another testament to the big six!

 

That does look like a little more than a dirty plug...

I am going to go with copper plugs since it is Not a daily driver, its a hauler/4x4 for snowy days. Honestly, I put less than 5k a year on any of my vehicles (I have 4).

I ordered one of those rotors, so thanks on that. I have the MSD cap and ignition, and now I am getting some Ford 9mm Spark wires. Should help my Idle pick up.

Its a 95 that runs fine once warmed, but idles bad at start up, especially in the cold. Its been sitting, so I am working my way through all the wear parts. As far as I know, the plugs are FACTORY at 109,000 miles. I have all the repair documentation (old people are weird), and I dont see a plug change anywhere.

 

Looks like my plugs were just a bit old...A testimonial to Motorcraft OEM plugs. The gap is over .100, my gapper only goes that far.

 

I just did a tune-up with new rotor & cap, wires and plugs. I went with standard Autolite copper core spark plugs and the rest of the parts were from United Ignition Wire sold by Rockauto. The cap and rotor fit great and has brass contacts instead of the aluminum. The wires themselves feel sturdy with solid contact on the plugs and coil. For those of you that like to color coordinate, the cap is blue! It was immediately noticed when I took it out for a check ride afterwords, no hesitation, sputtering or anything but good constant speed through the gears. I am completely satisfied and will use them from now on.