A recent WOT in the my stock A4 WS6 gave me (and my passenger) quite the scare. Around 5000rpm a very loud crackling sound could be heard from the engine. Almost sounded like a bag of microwave popcorn or rustling leaves being crunched! I slowed down and then did two more WOT runs. Both times it came back around the 5000-5300 mark. What could this be? I'm nervous to run it again for fear of damaging the engine.

 

Sounds like detonation to me.....better get it checked out!

 

yup yup thats pretty much what it sounds like to me too

 

Signs of you going lean, I would check some of the plugs, is there a big power drop at that RPM?

 

What was the weather like (extremely hot)? What type of gas were you running? I agree that it is most likely detonation. '

Possible solutions to help combat would be a lower thermo and fan settings. Run a higher octane. Use engine cleaner to clean up carbon deposits.

 

Try getting gas at a different station too - you might of picked up a bad tank. Had that happen to me once. Just take it easy on it till you run it down, then go to an Amoco and fill it up with fresh 93.

Also top engine cleaner like mentioned above - the dealer can do this if you don't know how or don't want to mess with it.

 

Are you running a Holley or K&N air filter? If so, check your MAF and determine if the little sensors are covered with oil/dirt glaze. If they are dirty (like mine were), clean them with rubbing alcohol and Q-tips. Use VERY light force on them...

Has cured my same problem.

 

Actually yes, I'm running the K&N FIPKII. I'll check it out. Thanks.