I tow pretty frequently with my 4 door JK and just replaced the stock plugs at 50,000. The factory plugs looked like they burned cleanly but the center electrode on all 6 of the factory champion plugs looked worn down. Anyone else replace their plugs yet in their JK? Regular copper plugs weren't available at the ol' Autozone so I put in Autolite platinums for 2.99 a piece. The main difference I noticed after replacing is the acceleration is smoother than before from 1000 - 3200 rpm. I do run 4.88 gears and turn a lot of rpm so I guess it's possible I'm burning up plugs quicker than others.
I usually don't put in platinum plugs in any of my cars unless they're installed OEM. I guess the JK's came with Champion platinum plugs?
Also had to dig awhile on the net but spark plug gap at .050 seem right? I couldn't find the gap on any of the stickers under the hood or in the owners manual.