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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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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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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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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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