Adam S

The stock Bosch plugs showed obvious carbon fouling upon removal. These plugs have about 16k miles on them and are almost 2 years old. The new plugs are Denso Iridium IK20 plugs (same heat range as stock).

I had been complaining to friends (and to APR) that my car would surge slightly at WOT. I was also not getting the greatest gas mileage. Well, the surging is gone with the new plugs. Idle seems a bit smoother too, so does power delivery (no surging). I'll bet my gas mileage increases too, but we'll have to wait for those statistics.

To all of you who are chipped, my tuner said that it's a good idea to change out the plugs every 10k miles or so to assure maximum performance.

When we pulled the plugs, the head also had obvious signs of carbon deposits. I run Redline Fuel System cleaner every 3-5k miles (another bottle just went in), so if you chipped 1.8t owners aren't using a fuel system cleaner, you might think twice.

Having said all this, I suspect that a new set of stock plugs would have fixed the surging too. I will repost after a few more tanks of gas. So far though, seems like a good idea to change plugs more often than the manual suggests. ;-)

Update: Yes, it's smooth power all the way to 100mph....

EdP

Tell me more about the cleaner.

Adam S

Supposed to clean out fuel injectors, cylinder heads, etc. Same idea as Techron. I get mine at Pepboys.

I also do a lot of short trips and my commute to work is only 3 miles, which is why I'm pretty regular with the fuel system cleaner. The head wasn't completely coated by any means, but there were enough deposits in there to get your attention.

Hey, there's nothing like crappy California gas!

audimods

<center><img src="http://members5.clubphoto.com/_php/view.php?ansen344311/May_13_2001/photo1@466682"></center><p>after 14.5k miles, the stock ngks has some deposits. nothing out of ordinary but our engines seem to be more deposit-prone than NA engines.

thanks for the post/email. glad your surging problem went away. I've adjusted my clutch switch closer to the pedal and my surging/over rev problem went away.

carace

that http://www.germanautoparts.com/ has some of the best prices on things. Maybe not everything but quite a bit of stuff and the customer service is outstanding.<ul><li><a href="http://www.germanautoparts.com/">http://www.germanautoparts.com/</a</li></ul>

WClark

Audi calls out Wynn's X-Tend V.I.C. Combustion Chamber Cleaner. Personally I swear by Techron.

See the service bulletin at: http://www.vwwebsource.com/vwtechcontent/audipdf/A99-12carbonwynns.pdf

Adam S

Yep, never found Wynn's at PepBoys or Kragen though. I've used Techron too.