Stick with the OEM plugs, too many have tried some "new fangled" plugs and they have had nothing but problems.

 

Well that bolt that i snapped, the first one you remove, holds the solenoid assembly down on top of spark plug... its a 6mm 100pitch 3 3/4" bolt, that not gm carriers nor local aoto parts stores, not napa, not lowes, nobody... i had to get the machine shop i work for to re create this bolt for me... so when YOur tightening it back down, as soon as it stops THREDING IN, DONT TIGHTEN IT, DONT WANT TO SNAP IT OFF LIKE ME.. LOL..

 

6MM 1.0 pitch = standard thread. PN 11519038 $4.00 on line.

The coil pack bolt TQ should be minimal, like 10-11 lb ft, one hand snug kinda thing.

 

did you guys ue the AC Delco Iridium plugs?

 

Just did plug change, took less than 1 hour. I have 100k on originals and they were shot. The gap was huge. Did not help with RPM dropping at stops, however they did need changing.

 

I used the ac delco iridium plugs to replace my plugs this weekend . No problems so far in the first 150 miles or so. I thought they were the oem plugs as per napa. I also read a couple threads in which other people used the iridium without issues. unless Im mistaken?

on another note....the owner's manual says gap at .042"....the repair manual says .044-.050......and the plugs said .043! i gapped mine at close to .043.

 

Mine were pre gapped at .041 and left em that way because the old ones were so big

 

Mine were pre gapd at. 41 and i left them that way cause after awhile the gap increases obviously looking at my stock 79,000 mile ones that were from. 45-.50 gap

Yes i used acdelco IRIDIUM ones... they are 110% perfect... if anyone els has problems with these, i bet its not the plug and more user error during the change, maybe plug not screwed in good, gap off, solenoid not booted on good, or not lubricated with the dielectric grease, or could be alot of things, but, im just an average, pre owned 2006 h3, changed my self not knowing anymore than i read here... acdelco iridium, great ride and idle...

 

i just changed the plugs on my '06 at 74k. 1st cylinder's a bear but otherwise a pretty easy plug change. smoothed out the idle, better acceleration and pulls stronger in the higher rpm's. be careful gapping iridium plugs. i checked mine out of the box - they were all at .041 and i left them. the ones i pulled out were gapped between .037 - .046


here's a form for a $2 per plug rebate on ac delco iridium plugs. it's good for purchases until 6/30/12.

http://www.acdelco.com/pdf/18-TP_H443020_SparkPlug.pdf

 

oem only for the h3