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Discussion Starter · #1 ·
01 AUG engine with 120k

Recently started to what I'll call stumble at idle or very low rpm. Engine will idle at 800 RPM then suddenly dip to 750 with a noticeable jolt. This is intermittent/random (can happen a few times every couple of minutes, could be longer between occurences). No surging. I can also feel it happen when coasting down to a stop (no throttle input). Twice now I've hit the gas (going from a stop) at the exact time of one of these which caused a CEL. I went back to check the codes, both times

16684 Random/Multi cylinder misfire detected
16686 Cylinder 2 misfire detected

Is the stumble due to coil pack issues? Is there something else I should check? I did replace the MAF about a year ago and the 02 sensor a year before that. If it could be something else, what would be the trouble shooting process?

thanks in advance.
 

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Discussion Starter · #4 ·
thanks for the responses. I am due for replacing the spark plugs, its on the to-do list. I'll try switching pack 2 and see what happens. If it is pack 2, can I just replace that pack or should I just replace all four? I haven't kept up to date on coil pack issues since the recalls, is there a particular part number to get (or conversely avoid)?

I'll also check the TB, probably needs to be cleaned also (just "re-found" taligentx's write-up).
 

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For the time being you can just replace the one, but with most VAG stuff, when one fails...you never know when the rest will. Unfortunatly these coil packs are quite expensive compared to the new revisions of the coil packs. If youre looking to upgrade, 034 makes a kit that will allow for the swap of newer coil packs. As for the part number, I'd need more information to tell you, or you can look at ECS tuning's website or something.
 

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Usually coil packs just flat out die. Any lean codes? Also check your pcv valve under the intake manifold. There should be two hoses connecting to the intake mani near the throttle body. Pinch off the hose that leads under the intake and see if the idle improves.
 

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Discussion Starter · #7 ·
Usually coil packs just flat out die. Any lean codes? Also check your pcv valve under the intake manifold. There should be two hoses connecting to the intake mani near the throttle body. Pinch off the hose that leads under the intake and see if the idle improves.
No lean codes, just the two I listed. I'll try to check the pcv this weekend... do I pinch off both hoses or just one?

So ECS lists two coil packs for the AUG engine, a "D" and a "R" version. Anyone know what the differences are or which is the preferred one?

thanks.
 

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My breather hose and T-housing leading to PCV are jacked up atm. Idling extremely rough compared to before (when just the breather hose was separated), and I've noticed same when coasting to a stop light.

There's a diagram in my thread, not sure how similar AUG is to AWM: http://www.passatworld.com/forums/4...-codes-p0303-p1136-diagnosis.html#post2845954 #2 was completely broken off the rubber T-housing it connects to...which was somewhat rough idle, now that I tried getting the T off it's much worse. Worth a peak, have to lean over the engine and look between gaps in the mani to see it.

VAGguy: How big of a detriment is driving the car with those breather hoses leaking to the point of very rough idle?
 

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Discussion Starter · #9 ·
Thanks for the diagram doyles-1.8T. Looking at that reminded me that I did replace the y-hose (#13) about a week before these symptoms started. The old one was completely torn through on the underside. Even with that leaky hose, I had no idle issues (stinky exhaust smell in cabin, yes).
 

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doyles, did you clamp off the line form the manifold to the PCV? That's the only thing I would think to cause your rough idle.
 

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VAGguy, PCV is certainly my problem - are you saying I should clamp that breather hose until I get PCV valve and hoses swapped out? Umm, zip ties or what? Seems vice grips are pretty risky.

wahoo, I'd say definitely investigate other PCV breather hoses down low if 13 was split up top. Even with that tube (plastic, not rubber) cracked and separating, CEL was intermittent - would stay off for couple weeks at a time.
 

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VAGguy, PCV is certainly my problem - are you saying I should clamp that breather hose until I get PCV valve and hoses swapped out? Umm, zip ties or what? Seems vice grips are pretty risky.
or try plugging it from the PCV side. yes. I honestly don't know what you could use to do so.

Lesson for anybody doing PCV work. buy everything ahead of time just in case. I've been there too, believe me.
 

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Well, I have the parts...swapping them out is easier said than done. That rubber T-housing is melted onto the f&#%ing pipe! Didn't even think to just try and cut it out, taking a box cutter to it this Saturday.

In the meantime, think I'll try a screw-on clamp to pinch off the section of hose coming right off manifold (think it's #10 in diagram, can't view from work). Don't really care if I damage, have replacement for that too.

Edit: Actually, could I just put new one on and stuff something in the other end for the time being? Have some extra check valves, maybe turn one the wrong way so air doesn't pass through?
 

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Edit: Actually, could I just put new one on and stuff something in the other end for the time being? Have some extra check valves, maybe turn one the wrong way so air doesn't pass through?
FYI, this seems to have worked pretty well. Installed new hose coming off manifold, put check valve on other end the wrong way so air doesn't pass through. Didn't realize how bad the idle had gotten, feels 10x better after doing this - hope it holds for a few days until weekend.

Sorry for threadjacking btw, mods pls transfer to my thread if needed.
 

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Discussion Starter · #15 ·
Sorry for threadjacking btw, mods pls transfer to my thread if needed.
LOL, I don't mind 'cuz I did learn from your posts but it was a nicely played thread jacking!

I ordered coils and plugs last night and will be checking the PCV lines this weekend.
 
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