Spark Plugs

[chazsandiego]

Months ago I replaced my plugs with some randrom, cheap NGK's from autozone. All was good until I recently decided to swap them with some "good plugs" Autolite Double Platinums.

That was a mistake, as I know now from johans page that I need Bosch W8LCR / W8LPR for the m30 engine but a forum post back from 2009 stated they had been discontinued.

Autozone told me the autolites were the best and I even goose chased them down (lesson learned). So that being said...

What plugs could I use?
What plugs should I use?
What plugs do you all use?

Thanks as always!

[NE32]

From what I've been told/read, Platinum plugs are kinda useless (in the m30 at least). Definitely correct me if I'm wrong. I've used Bosch 7909, NGK ZGR5A, and cheap Autolites. I was meh on the Bosch plugs. I like the NGK plugs. Used the Autolites here and there. Never had any problems with them but more of buy em if I need em. The NGKs are on top of my list. I will say I did blow out one of the NGK plugs for whatever reason but other than that, they've been great.

[CroughtonE32]

I have your exact motor and same year. I've never used anything other the Bosch W8LCR for almost 28 years. Never had a single problem. You can get them for a buck fifty each at BavAuto. I can't see any reason to even try another brand. It's what came in the car and I've probably changed them 4 times.

[chazsandiego]

Appreciate the replies! I'm gonna grab some NGKs today and grab the Bosch plugs for next time.

I would wait for the Bosch plugs but these autolites are causing some issues. Rough idle, check engine light, car refuses to accelerate over 65mph and will stall without the engine dying around 70mph. Stomp test is giving me code 1222 "Lambda Control System Bank 1" and I'd be willing to bet that these double platinums are messing with my fuel mix.

Also, how important is it to set the gap on the plugs? And does the .7mm-9mm gap apply to all spark plug brands? I didn't gap the cheap plugs and had no issues.

[shogun]

Normally no need to adjust the gap, they are pre-gapped. Also mentioned in the quick finder for example on the NGK site http://www.ngksparkplugs.com/
For example ZGR5A gap 0.036 in

[chazsandiego]

Got the correct plugs in, autolite copper. They were the only plugs in stock with a removable/threaded terminal stud. All the others had a fixed stud and would not fit my spark plug boots. I also did not gap the plugs as it stated on the autolite website that they were "pre gapped" but may need to be gapped, go figure.

I must explicitly state that you should NOT use double platinum spark plugs on a stock m30 engine. They didn't break my engine but they did cause me a couple gray hairs.

Greatly appreciated they feedback as always!

[NE32]

How does it run now? Assuming much better?

Got the correct plugs in, autolite copper. They were the only plugs in stock with a removable/threaded terminal stud. All the others had a fixed stud and would not fit my spark plug boots. I also did not gap the plugs as it stated on the autolite website that they were "pre gapped" but may need to be gapped, go figure.

I must explicitly state that you should NOT use double platinum spark plugs on a stock m30 engine. They didn't break my engine but they did cause me a couple gray hairs.

Greatly appreciated they feedback as always!

[chazsandiego]

The vehicle is driving excellently now! Response is a bit better than the NGKs but nothing dramatic. The car may even be able to hit 105 or so now but I wouldn't know. I only drive the speed limit...