Iridium Plugs
 

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You are running pretty lean!

Need a lupe to read them correctly as there is lots of lighting issues and exposure issues with the posted images

Any big box local auto parts store should be fine - Advanced Auto, Pep Boys, O'reilly, Autozone, etc.

If I can get free shipping, ECS Tuning is a good source.

I don't like Rockauto that much because their stuffs usually arrived with boxes all smudged/dinged up, like they're from closed out inventories from people going out of business...if you know what I mean.

I use fcp euro on any vehicle I plan to have for more than a year or so. That lifetime warranty comes in handy even though they are usually 5ish% more expensive than other etailers.

No worries. I hear you on the cheapskate tendencies. I still use HEB (Texas grocer) premium most of the time vs other mainstream brands. :D

I have been experimenting with QT's ethanol free gas a little lately though. Will see how that goes.

I use Shell premium. I got lazy a few times while shopping at Sam’s Club and used their fuel. Never again! I had problems every time. I never fill my E53 pass Half, I like to keep fuel as fresh as possible. I’ve also had fantastic results with Lucas fuel additive.

PLUG INFO
 

Now that I looked at these plugs on a larger screen, I can tell you they are NOT IRIDIUM NGK plugs. Take a peek at the center electrode diameter, it has to be 2x the correct dia size. By the way those little silver spots appear to be piston material from octane pinging (KNOCK) where combustion temps exceed 1200 degree F. NOTE: Aluminum melts at 1200 degrees. (See chart below) Cheap gas w/ poor blends (see Calif regs for details as you all get crap mixes to satisfy CA Research Board) results in really poor combustion consistencies tank over tank.

Call NGK direct to confirm with tech specialist who will have you read off the shell numbers and he can confirm manufacturing batch numbers.

Anything that has volume and profit attracts knockoff suppliers. Copying packaging is easier now than ever with high speed color scanner/printers. Welcome to technology. It happens on anything electronic, medical, and most consumer products. Happened in the fastener world where they flooded all SAE/Fractional grade 8/8+ bolts with similar marking on grade 4/6 bolts. Rotary craft started to fall out of the sky with blades missing as they sheared off. 80% of the US inventory was junk from offshore, heads were marked as if it was produced in the USA.

Aluminum 1220F
Aluminum Alloy 865 - 1240F

Thank you for the info. already ordered new Iridium plugs from Rockauto. Assume they'll be genuine. Doesn't the ECM adjust for knock to prevent it? I've been running nothing but premium, so signs of knocking are surprising.

GREAT info. Thanks for posting. That had been my suspicion, but since I did not know enough, I was waiting for a more informed analysis.

Based on experience with all my cars and reading stuff like this situation online, I really think the #1 consideration when getting new spark plugs is to make sure they are not fake. Well, I guess after you make sure they thread in there. And after they do not collide with the pistons. But after that ... :rofl:

When I got my '01 3.0i at around 169k miles, I soon replaced the plugs, just because I had no record of them being replaced and was foolishly dreaming of higher MPG. There was no change at all in anything about the car after replacing with the exact specified NGKs (but not genuine BMW). The ones that came out said BMW as well as NGK on them, and I'm pretty sure they were original. The electrodes looked close to perfect, even at that mileage.

Glad to help
The knock sensor has to hear the knock and the O2 sensor info are compared then the injections respond with a longer or shorter pulse width (more or less fuel, think of a garden hose pistol more or less full on pulses)
Meanwhile the pinging has happened throughout the last 3-5 strokes.
New technology sees it at the per stroke. Oh and per cylinder. Ours only sees a bank not at the cylinder. Clogged injectors only make the issue worse. Add some Techron injector cleaner made by chevron if I remember correctly

Glad to help you also
Fake plugs just started as it was a non issue when I worked for Champion. There were a few Mexico shops buying old stock and repackaging them and then stuffing them into the market. One group even picked up old plugs, cleaned them and resold them in sets! The labor must have been cheap!