Just need to know what copper plugs I should get for the Libby. Also where should I get them ( advanced, Nappa, etc )? I'm trying to get ones that are already gapped also. I keep getting a miss fire code even though I changed my coils and plugs. I put in the platinum plugs but I hear the copper ones are better.

Champion or NGK(I personally don't recommend these).Always recheck the gap and set via the emission sticker on the radiator support.


Misfire codes can be caused by other issues also,not just plugs and coils.

Troy, what plugs do you recommend?

As a former mechanic, a sure sign that a shade tree mechanic has worked on a car is if it has the platinum plugs in it.
Personally, back when I was turning wrenches I never liked champion.
There is no magic in spark plugs, the NGK's will work fine and I always get copper because when I pull them out I know what the engine is doing, the platinum leave me blind.

_________________
2002 KJ Limited 3.7
Completely Stock
215/85R16 Kevlar

So what other problems can a misfire be caused by?

Champion copper cores.

I'd never put Champion plugs in anything either but Chryslers love them so that's what goes in.

Bad PCM(bad coil driver or injector driver)
Bad wiring to coil/injector
Bad/plugged injector
Head damage(broken valve spring,valve seat coming out of head,and rocker falling off)
Internal engine damage

Sweetness!