Rythmic Sound from my Engine at idle - 3 cylinders?? Please Help!

[boilerdam]

So, this morning, my car was making some really weird sounds after the initial warmup; I uploaded a clip to YouTube. Could you please help me diagnose this? I fear this might be a bit expensive...

YouTube link: https://youtu.be/3pDA1ygBM_U

Issue:
- Engine was making a sound with a weird cadence after the morning warmup

Symptoms:
- Car was rocking from side to side
- The rocking was enough to shake an open door (about 0:30s in the clip) and my legs while sitting inside
- No engine codes (can be seen in the clip before I get out)
- Almost bogs down in 1st gear from stand-still
- Almost stalls when rolling without throttle input (our anti-stall keeps it at the min rpm to prevent stalling and lets the car coast without throttle but not so today)
- Smooth enough, almost normal, past 20-30mph in & beyond 3rd gear, no extra revs needed. Cruised at 80mph on the freeway and it was just fine
- Low torque while starting from stand-still

Existing conditions & problems:
- Battery almost completely dead. Trying to replace but stuck with the bolt on battery hanger. Battery retains enough charge after some running. Been using jump starter for morning starts for the past 3 days (including today)
- High vibrations from the engine sometimes (non-weather related) for the past 2 months. Goes away on its own. The high vibrations started after some spirited driving over bumpy downtown Los Angeles roads with a number of rev-matching downshifts.
- If I redline 1st gear, engine gives out a loud howling sound and the high vibrations start. (I never redline, always keep it around 2500rpm, 3000rpm max; I only redline to see if it triggers the vibrations)

Recent repairs:
- 3000mi ago: Carbon cleaning, replaced injectors & spark plugs after a cyl-2 misfire code
- 2000mi ago: Changed wheels & tires

Other info:
- Car is completely stock except for a Carbonio intake
- Car has 104,6xx mi on it
- New rev DV
- Snub mount replaced 50,000mi ago; engine mounts replaced 45,000mi ago
- Timing belt has not been replaced although I'm aware that I'm coming up to the point it should be done
- Still on stock clutch (AFAIK. I bought the car with 32,000mi on it)
- I don't drag/race. I baby it as much as possible

Is it running on 3 cylinders? timing belt? or flywheel damage? or engine mounts? [that's probably in decreasing order of $$]

[allstock]

Scan it for the codes.

[Charles.waite]

From that description and sound it really seems like one cylinder is missing.

I left a coil unplugged once and didn't realize it and the result was similar. Scanning should help isolate WHY that missing is occurring.

It could also be a really bad vacuum leak somewhere.

[boilerdam]

My OBDII bluetooth reader wasn't working (what are the odds that it stops working today) but I took it to Auto Union Tuning in Huntington Beach. They read the code as "Camshaft Correlation". Seems pretty scary!

FYI, the check engine light came on when I left for lunch from work. All other symptoms remained the same.

Quick googling tells me it's a solenoid problem and AU Tuning, understandably, don't want to mess with it (rare, complicated problem that might not have a fix from their experience).

Future plan: I'll try some troubleshooting methods that others have done in the past. This guy on Audiworld had the exact symptoms as me. Apparently, and as the guys at AU Tuning explained, it's a solenoid that's most likely stuck either by metal shavings or debris.

The guy on Audiworld but got it to work by shocking the solenoid but that doesn't really solve the problem if there's metal shavings inside (the metal mesh/screen sometimes fails, per Audi).

There's a slight chance that camshaft-related issues are covered by a factory warranty (10y/120,000mi), I'll confirm with the dealer or AoA tomorrow.

Edit: Btw, on my way back from AU Tuning, the code went away and the engine was running just as it was before. So, whatever it is, it's intermittent... for now.

[allstock]

If it's the camshaft solenoid (N205) just change it out.

You have "vagcom" typed at the bottom of your posts. Why not scan it for a more thorough diagnostic.

[boilerdam]

Yeah, my first test is to change it. I'm trying to find documentation on how to find the damn thing in the first place :)

My VAG-COM mods were done with the cheap cable (seatbelt chimes, windows rolling etc), doesn't do any diagnostics. But I did reply on a local SoCal thread for people who have the cable that might want to lend them for a short time.

[allstock]

Sticking out on the passenger side of your cam chain housing with an electrical connector. New ones are about 130, I forget.

[boilerdam]

Thanks, I found 2 threads:

(1) Shows the location of the valve: http://www.audizine.com/forum/showth...-location-pic)

(2) Similar problem: http://www.audizine.com/forum/showth...about-the-N205

I'll follow through on these later today and see what best I can do. BTW, you were close - the valve is $144 on Europaparts.

[Charles.waite]

I've got a working spare if you want it. Came off my 2008, was original and only has 60k miles on it. I replaced it as a troubleshooting step which didn't seem to make any difference. If you want it shoot me a pm and we can talk. I'll let it go cheap since I've got no use for it.

It's a suuuuper easy swap. 5 minutes at most.

[boilerdam]

Thanks, Charles! I'll definitely take it. However, I saw your comments on the other thread, was quite informative. I checked mine and I don't see any oil around the connector. I didn't try taking the valve off but nothing's leaking outside. I'm guessing it's filled with debris inside and since the CEL went away and the car is normal-ish, it's more likely debris.

I'm taking it to the dealer to diagnose it as well - hopefully, it's not something major - they charge $100 for a diagnosis. So, I'll see what they have to say - I don't want to mess with anything if there's a chance that a warranty might cover it.

I was going to PM you anyway since you were active in that thread. Did your car sound like mine from the video I posted? Were you able to figure out what was wrong with yours?

Yeah, it looks like an easy swap - 2 Torx bolts on either side.

[zeitmorder]

I saw your youtube video . Mine did the exact same thing when a coilpack/sparkplug went bad. I had replaced both since I was still on the original plugs @ 89k and on my 2nd set of coil packs (first set covered under recall). It sounded and ran like a lawnmower above 3k rpm and was accompanied by a flashing CEL. Runs great now.

I happen to work in south Irvine (Spectrum area) and have an Autel Vag Code Reader if you need help reading codes.

[Charles.waite]

My car never ran rough at all with the issues I had. It seriously ran as smooth as any other 2.0t even with the pump tip broken off and the follower worn 1/8" up the sides.

[boilerdam]

I saw your youtube video . Mine did the exact same thing when a coilpack/sparkplug went bad. I had replaced both since I was still on the original plugs @ 89k and on my 2nd set of coil packs (first set covered under recall). It sounded and ran like a lawnmower above 3k rpm and was accompanied by a flashing CEL. Runs great now.

I happen to work in south Irvine (Spectrum area) and have an Autel Vag Code Reader if you need help reading codes.

Thanks, zeitmorder! I'll probably take you up on your VAG code reader offer sometime next week; I'll PM you. I just dropped mine off at Audi South Coast for a diagnosis. Let me see what they come back with. But I do want to do some data logging with the blocks that pertain to camshaft timing.

Yes, vibrations on mine (about 6months ago) went away after changing the sparkplugs & coilpacks but this new CEL came one and from what I've read about the camshaft solenoid, they could all be related. I'm just hoping it's just a solenoid to replace although I didn't find anything wrong while troubleshooting last evening (checking for leaking oil around the solenoid connector).