I just recently installed the Autolite's, and haven't really noticed any difference at all.

 

That does not surprise me at all.

 

I stick by the assertion that the copper plugs make it idle more smoothly...in my experience. It is not a Lexus, but it is noticeable. Also, I drive the exact same road to and from work every day. My mileage average, as stated by the trip computer, was consistently 13.5 - 14.5 it is now 15 - 15.5

 

Well, I just finished a full tank of gas with the new plugs, and I actaully have worse gas mileage!! And, yes, I gapped the plugs properly. Oh well, the decline in gas mileage isn't enough for me to swap out the plugs with the ones I had.

 

Your talking about the 3923s right?

I knew this was coming around sooner or later.

I see that older dakotas are using them too, on like the 3.9s and stuff, this plug gets around.

I'm glad I went with the 5224.

 

OK, bare with the new guy here...the majority opinion seems to be the 3923, copper, gapped at .040. Was going to do my 4.7, non H/O this weekend and wanted to be sure I understood everything...
Thanks...

 

Didn't really like the 5224's but after about 600+ miles on the 3923s she's acting like she was before.

 

Only 600 miles, that sucks..just picked up a set but don't know if I'll put them in or not now. All that for 600 miles..

 

Yea, back to kind of a crappy idle. Not sure if a bad fan clutch could have something to do with that or not, but mine is bad. Need to throw that electric on when I get back home.

 

More spark plug info and opinions..
http://www.dakota-durango.com/forum/...php/t-569.html