boarderkris

Hey folks,

After going through many threads, I've found many studder issues, but none seem to be quite the same as what I'm experiencing...so I'll make this post.

I have a 2009 A4 2.0, and when I start the car cold (which forces the idle to ~1250rpm for ~30sec), I get random studders. It almost feels like random mis-fires, but I've never thrown an engine code, and have never triggered the check engine light, so I don't believe it is a mis-fire. As soon as the idle resumes its regular rpms (~900rmp), and from then on...all is good! It never studders again. If the car is warm, thus starting with an idle of ~900rpm, all is good as well.

My guess right now is that it is the PCV/PRV valve..causing the presure around the cams to be off....because, if I remove the oil cap, while in idle (~900rpm idle), the car makes the exact same studder.

If you have experienced this, or have any thoughts..let me know. I know others have mentioned the plastic intake manifold for issues like this, and it may be that as well..but I have a hunch that it is not this.

Thanks!

Kris

dk1

Search deeper. There were threads about this before. If your car sounds like a diesel truck for about 30 seconds, it's normal. The car must be cold (as parked overnight) for this to happen.

Edit: found one thread
https://www.audiworld.com/forums/sho...hlight=reverse
The guy was backing up from the driveway so he thought it was related to the car being in reverse. Comes with a video so you can check if it's the same sound.

Crucible35

I had the exact same thing (as have many '09 B8 owners)for the first year of ownership on my '09 and it went away after my third scheduled maintenance. Don't know if it was a software update. Still can't explain it.

There have been many threads about this issue....rest assured you are not alone....although still a mystery why it happens. When I would have it, i touched on the throttle to give it a little extra juice and it would go to the normal 1300 RPM warm-up for 30 seconds.

Nostromo

I had the low stuttery-idle-on-cold-start problem happen twice in a week. Since then I've switched to exclusively top tier gas (was filling up with Cotsco 91 before then). Problem seems to have gone away - it's been 4 weeks.

I also make sure to floor it in sport at least once per commute to help blow out any buildup. Don't know if that helps, but it's sure fun.

boarderkris

LOL. That doesn't sound normal at all!..my car definitely doesn't sound like that! Car sounds fine, its just the random studders.


I could see gas doing something like this, but I have only ever put Shell 91 octane in both my A4s. So I don't believe its a gas issue. Unless these engines are not happy with whatever Shell is mixing in these days..


There must be a solution!

Turbo Freak

Mine sounds like a farm vehicle for the first 30 seconds, but I think it is because my garage amplifies the sound !

NPuter

I use 93 octane and get the weird "wooshing" noises every morning. However, once the idle drops, everything returns to normal.

There was a discussion about this on audizine. I believe there is a TSB for an update that eliminates this.

boarderkris

Yeah, I've always had that wooshing noise, which doesn't really bother me much...Just sounds like air is being sucked really really hard!
..its this studder that shakes the car that is definitely not normal.

dk1

I may have exaggerated a little (ok, quite a bit) but my car sounds noticeably louder with a bit of vibration. Open windows or driving out of a garage definitely amplify the effect. But since it definitely looks computer controlled (you can see RPMs being high and then drop) I am not concerned. I use Shell 93 gas almost exclusively.

iflywoe

check the plugs and do a software update at the dealer, that took care of mine