2012 Denali spark plug change, iridium or platinum?

[dkad260]

The engine runs smooth but is slightly rough for the first minute or 2 when first starting cold, motor has 92K and I just purchased last month.

So to be curious I pulled the #1 plug and the gap is .039 and is a 41-110. I've heard of others switching to the platinum in the 5.3 but curious if the consensus is to stay with the iridiums for the L94.

There was some corrosion on the plug boot so I may just replace the plug wires at the very least.

If I'm going to pull all the plugs to check I will replace them, would like to hear thoughts or recommendations on both styles of plugs.

Edit to add: I see the 41-162 is the current recommendation per GM.

 

[wsteele]

The engine runs smooth but is slightly rough for the first minute or 2 when first starting cold, motor has 92K and I just purchased last month.

So to be curious I pulled the #1 plug and the gap is .039 and is a 41-110. I've heard of others switching to the platinum in the 5.3 but curious if the consensus is to stay with the iridiums for the L94.

There was some corrosion on the plug boot so I may just replace the plug wires at the very least.

If I'm going to pull all the plugs to check I will replace them, would like to hear thoughts or recommendations on both styles of plugs.

Edit to add: I see the 41-162 is the current recommendation per GM.

At 92K you are within spitting distance of the 100K replace plugs and inspect wires paint cycle (which is French for me to replace the wires as well). I will say, .039" would indicate the plugs are fine wear wise (gap usually grows and .040" is factory new spec for the gap).

I just use the OE plug and wires.

 

[gooffeyguy]

I replaced mine about a year and a half ago and used the same part # I took out, which were 41-110 at the time. I see now that part # is superseded by 41-162

 

[Foggy]

Irridium all the way !! And do your wires at the same time..
You'll prob end up ruining a few of the wires trying to get them off anyway
and at this age and mileage they are toast too !

 

[FrankU]

The plugs are supposed to be properly gapped out of the box , don't bet on it. Gap the plugs.

 

[dkad260]

Thanks, I will use the iridiums, I figured that was the case but wasn't 100% as some have gone to the platinum with the 5.3.

I did get the wires changed yesterday, there was a decent amount of corrosion in the boot at the spark plug clip, made a noticeable difference in the cold-start idle smoothness. Had a lot going on yesterday but the plugs will soon follow.

Yes, I did damage one boot while removing it.

 

[TollKeeper]

Yes, I did damage one boot while removing it.

Let me guess, the passenger side, rear, #8.. Those seem to always be the worst.

 

[dkad260]

Let me guess, the passenger side, rear, #8.. Those seem to always be the worst.

Well, it would have been for sure, actually was #6. I had minimal leverage so I tried to gingerly aid the boot by a light tug on the wire...fail...lol.

For #8 I used a long-reach needle nose on the recess of the boot, with a wooded dowel as a fulcrum against the valve cover...definitely tight back there.

 

[TollKeeper]

I know I have a tune up in my future.. I just did one on my Envoy V8.. #1 is by far the worst! #8 is the second worst.

The #1 plug is completely behind brackets, hoses, wiring.. Its just jammed in there. Installation by Brail.