The ngk plugs looked fine, almost new still. I read before i changed them out to the NGKs in the first place that our trucks are very in particular about plus. Strange.

 

Reason I asked is the plugs on my current truck are quite white, even after 8000 miles , whereas my former rams they were always tan around center electrode. I've tried both ngk and stock copper champions. I even put the autolites back in that were in the truck when I bought it. Most advice on the forum and most spark plug websites say the plugs should have a tan color.

 

the ngks were more tan than white. i only had the ngk's in there for a few hundred miles though. Try and get new autolite xp5224's use plenty of dielectric grease and keep pushing the wires until you here the click. the 5 and 7 cylinder were really tough to get on all the way. they felt on even when i tugged but i wasnt happy with it so i kept pushing and it did click.

 

I've had the same issue that you guys have been having. I even had a check engine light come on that checked out as misfiring in the number five and seven cylinders. I cleared the codes and it has not relit. I believe I'm going to check out my new plugs now. I'm just learning about this plug pickiness in our 5.9's, thanks guys.

 

They are also prone to misfire from routing of the plug wires. There is a TSB on a reroute of wires. I also use some cheap loom spacers to keep the wires away from each other at the plug boot. 5 and 7 are next to each other in firing order.
My opinion is that changing spark plugs brands isn't going to alter or fix a shaky idle, unless there was something wrong with the plugs changed out,or the wires may have been routed different causing an improvement. Overall opinion leans to using stock copper plugs, although, I recall a very smart guy who used to post on here a lot used some fancy platinum tipped plugs. I think he also had magnecor wires, a hughes f-1 intake, billet fuel lines and other mods.

 

when you say reroute to wires you mean as in where they rest right? not a different firing order from whats in the service manual? and how does the way they are routed affect anything?

 

There is a Tech Service Bulletin for plug wire routing in the FAQ section here. Firing order remains the same, as that is determined by engine design, not a trivial matter to change it.

Plug wires running to close to each other can generate 'cross talk', and you end up firing more than one cylinder at a time. That gives weak spark on BOTH cylinders, and can be seen as a miss. Depending on just where the 'other' cylinder is in its cycle, can cause other problems as well.....

 

oh i see. ill look into that as well. would covering the wires with the plastic sheath tubes work as well instead of rerouting.

 

Nope. They are high voltage, physical separation, or a really good quality set of wires are the only options.

 

Pulled plugs for the first time since the plenum repair and new timing set, approx 1500 miles and instead of really white plugs they dark, mostly on one side, almost light soot. So air/fuel ratio sure changed. Still has the jiggle at idle, but not as bad as last year when outside temps got up in the 40's and 50's. #4 plug actually had some oil on the center part after sitting overnight. Just a tish. Deciding whether to try some different plugs or not.