I know a lot of people like NGK Iridium plugs. I'm using Autolite double platinums right now. Theyre a decent plug. I dont have any mods tho.

 

NGK Iridium seems to be most preferred.

 

I've been running NGK iridium IX for a while now with no issues.

 

Cool thanks guys. I'll go with those. Does anyone have any info on installing them on the coupes?

 

08 3.5 LZ4 .....Yeah get ready for one hell of a time getting the back three boots off. :banghead:

 

Take off as many parts as you can to gain better access then have lots of patience and eventually they'll come off.

 

Interesting that most folks don't stick with the OEM delco plugs. I'm up to nearly 50K miles and am planning to change the plugs as it's been 7 years! I might use NGK as it's what I use in my other vehicles.

 

Pretty sure the OEM plugs are made by NGK iirc

 

I just changed the back three on mine at 33,000 miles while I'm changing the crossover pipe gaskets. I had to remove the alternator, and so much other stuff that I could easily get to the rear plugs. The stock AC Delco plugs are Iridium, at least on my '08 3.5, and show absolutely no wear or gap change. They are designed to go 100K miles, and probably will just fine. I put the same part number Delco plugs back in.