Thanks Hxgaser. Although this is a corn snake, somehow I don't think it'll taste like corn. I tried to grab him/her? & it slithered down below the Y pipe & over to the transmission. Bringing car into garage tomorrow for another attempt to fix the never ending missfire issue, so I hope the snake decides to leave tonight.

 

CRuby,

I am really curious what you discover. Please find some time to post about it.
I am facing a similar problem on my 2001 Allroad with 103K on it.
Started misfiring on bank 2 and mainly cyl #6 is the most frequent offender. Only on idle. When it warms up misfire of up to 50 count stays only on cyl 6.
I have played with typical intention components parts, eliminated small vacuum leak, reconditioned injectors (all came back with 2% flow tolerance) but it changed nothing.

The car runs great otherwise but has thrown two codes on different occasions:

17930 - Camshaft Adjustment; Bank 2
P1522 - 35-10 - Malfunction - Intermittent
17755 - Camshaft Position Sensor 2 (G163) / Engine Speed Sensor (G28)
P1347 - 35-10 - Incor. Correl. - Intermittent

Oh, ... once I got tempted an put some sea foam in the tank, a tad more than prescribed. After 70 miles I checked idle and misfires were gone. Got excited, but after I came back home (another 70 miles) and checked it again and they were back /.

I am starting to wonder about the info you got from your mechanic related to the chain stretch. Perhaps it is time for new chains on both banks to get done with it?

 

I've been busy on other projects, but now getting back to the A6. It's back in the garage & 1st getting ready to look for any vac leaks before going deeper. Have several new parts. Changed both upstream O2 sensors. One of the old ones was slightly out of spec & I figured they've never been changed before, so they were due. Definitely need a crows foot O2 socket to get these off. Soaked a bit with PB blaster & off they came. I've read drivers side would be difficult, but using long extensions & u-joint made it no problem.

I also got 3 new coils, because old ones had broken flanges from prior owners/mechanics trying to pry them loose. Also have new cam chains & new tensioner shoes. Will eventually get these on too. I'll try to measure old vs new chains to see if I can notice any length difference.

Lastly, THE SNAKE'S NOT GONE YET! Found ~3 ft. snake skin on the w/w blade the other day. I had the air box & MAF sensor removed & had forgotten to block off the intake holes. Hope he didn't go into the Y pipe. Probably running our smoke leak test tomorrow, so if he's in there he's going to get smoked.

 

I am very curious about the results of chain length comparison you are planing on....

I also wonder if you can tell if the cam adjuster pads look noticeably worn out.

I have put another few hundred miles on the Allroad driving it to the mountains and registered only misfires on cylinder #6 and multiple misf. code as well. No other or camshaft related codes appeared.

 

Last time we had tensioners out the shoes showed only slight wear at the chain track. I didn't mic it but I'd swag it was 5-10 mils. Didn't look bad to me, but since I'm doing related stuff I figured might as well. They are brown/black from being cooked in engine oil for 133K miles & 12 years. No chips but I wouldn't doubt they are brittle. I'll snap some pics & maybe write a DIY, since I hadn't found any on changing shoes.

On your problem with misfires on 6, I'd focus on potentially something bad on that cylinder. If you have coil-on-plug, like me, I'd suggest swapping coil with another cyl, & maybe swapping plug too. If misfires follow the coil, then you found the problem...new coil needed.

Probably won't have cam chains out for week or 2, as we're taking our time.

 

I see.

Well, as I mentioned, on mine, I have tried the usual suspects of swapping electrical including plugs/coils/ICUs. I have fixed one small air leak. I have pulled and cleaned injectors too (send them over for service) and none of that helped. The misfires are only on idle and do not move from cyl #6. And #5 and #4 will occasionally misfire too but I think it is caused by #6 as it reports counts of ~50 while the others only one or two per measuring cycle.

 

Status:
Replace cam chains & slightly worn tensioner shoes. I now know they weren't part of my problem. It's the easy thing that I overlooked. I never checked the spark plug gap on the plugs installed by previous owner. Duh!!!! I did now & find that they're all gapped at .040"-.042 . Too BIG! Changed plugs with NGK's gapped @ .030" straight out of the box & no more missfires based on last nights test drive. Odd thing is bentley manual calls for gap to be .4mm-.6mm (.016"-.024") while NGK lists gap to be .032" . Quite different. Still throwing cam-crack correlation codes for both bank 1 & 2, although engine feels smooth. Cam chains on per previous postings & the cam lock bar fit perfectly even after multiple turnovers by hand. Later this week I'll probably use vagcom to read cam-crank phasing, but for now car's seems to be running smooth. Finally! On to other issues such as rear speakers.

 

CRuby, couple of questions for you.

1) did you replace the chains and tensioner shoes and spark plugs at the same time?

2) did you have a chance to measure the chains?

Thanks

 

Yeah I changed cam chains, tensioner shoes & plugs at same time. Old shoe wear seemed relatively minor, & couldn't figure a good way to measure the chain difference. Our success was short lived. Problem came back after a couple of days of driving. Hooked up vagcom & now the MAF sensor provides a value, but it doesn't change at all while driving. It should. So this is next on the list to hopefully fix problem. I suspect an intermittent reading from the MAF.

 

Remanf MAF didn't cure the problem either. Bit the bullet & brought car to a german car shop. They were surprised I tackled the timing myself and gave lots of cautions, like using the right tools, properly aligning cams, etc.
Anyway, they pulled VCs, check the cam chain count & redid the TB timing, put it back together anddddddddddd the problem still exists.!!!
Cams on both banks out of correlation to crank & misfires on all cylinders. Again.
Now I need to deal with paying to not fix the problem. He mentioned it might be the cam tensioners...but they check out OK with the various tests I ran before. I can guess that just as well, but was hoping for more definitive diagnosis.
I'll change them, if need be. I'm skeptical that both sides go bad together & they can be bad, but have proper checkouts, including passing solenoid activation check.

Way back when, on my second time through this I had added one roller count to cam chain on bank 2. That had changed the vagcom group 094 phase readings from 25 deg KW for both bank1 & 2 to -5 deg KW on bank2? The -5 is within spec of 0 +/-6, so now I'm thinking that I should consider going back to that & try similar change to bank1. Afterall, what do I have to loose, as long as I don't introduce the valves to the pistons. There must be a cure to this problem. The to do list now is:
1) Get car back from shop
2) change chain count
3) maybe new tensioners
4) maybe ECU?
For ECU, I know capacitors can go bad & show bulge or leak. My other son's Lexus ran like crap with a bad ECU. Maybe it's triggering this incorrect correlation & misfires? Who knows. Maybe I'll pop it open & look under high mag at work.
Well, I never thought I'd be messing with this problem for so long without success.