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rough idle help

12bluemk6

Ready to race!
Hey guys,

Some of you might have seen my thread about spark plug/coil pack issues. I have had a mechanic check em out and he thinks they're fine. So I have a question...

I'm getting no codes on Torque, however I have a rough idle(not too bad) which shudders every five seconds on idle. I'll have to double check and make sure its the same when the car is warm.

Could this be the pcv valve? There's a little oil and crap around my oil cap on the rubber seal it sits in... Is that a sign of pcv failure? The pcv doesn't seem to be leaking from what I can see.

Like I said, no codes, but rough idle. Which makes me think vacuum leak...

Any help is much appreciated.

EDIT: Is there a way to test it so I can bring it in for warranty and say that I know for sure its the pcv? They blamed the rough idle on new plugs and r8 packs and then quoted me for $330. I lol'd.
 
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Jaber

Modero
Even if you test it and show conclusive data, they'll want to conduct their own test/analysis.

If the dealer isn't cooperating, bring it to another dealer. :iono:

Do the test Boosted mention above. Or find someone with VAGCOM (unless torque logs this) and log short term and long term fuel trims.
 

jwal

Ready to race!
Check your hoses around your PCV as well. I had one come loose and caused an influx of air into my air fuel ratio.
 

12bluemk6

Ready to race!
goodluck. keep us updated. make sure your coil packs seated as they tend to pop up a bit .

Your post reminds me of another thought. I went to a mechanic who works on a lot of vw/Audi's and he said that if a clip broke off of the coil pack harness it could cause a rough idle. Is this true?

One broke in the middle, the other 3 are fine. The r8 coil packs are weird they don't seem to sit as far down as the stock ones. Is this wrong? Do I need to push them down harder? I don't want to break anything.
 

Jaber

Modero
Your post reminds me of another thought. I went to a mechanic who works on a lot of vw/Audi's and he said that if a clip broke off of the coil pack harness it could cause a rough idle. Is this true?

One broke in the middle, the other 3 are fine. The r8 coil packs are weird they don't seem to sit as far down as the stock ones. Is this wrong? Do I need to push them down harder? I don't want to break anything.

The R8s look like they sit higher, not sure if its illusion or physically the top might be a bit taller. But as long as you push down as far as it goes, should be fine.
 

12bluemk6

Ready to race!
The R8s look like they sit higher, not sure if its illusion or physically the top might be a bit taller. But as long as you push down as far as it goes, should be fine.

Okay so that's checked off of the list. Any thoughts on the clip? I saw other threads about it and everyone said that it shouldn't make a difference.

This is really bugging the shit out of me the dealer can't figure it out, blames it on plugs saying they aren't OEM, which I confirmed with Napa that they are the correct part number. Do I really have to drive an hour to get to a reputable dealer? Lol I really need VAGCOM.

Another quick question: I took out the new plugs put the old back in with r8 packs, same intermittent shudder. Old coils, no change. Now running old plugs with r8 packs, is it a bad idea to put the new plugs back in again? Should I just buy four more new ones to be safe?
 

Jaber

Modero
VAGCOM is honestly needed with this car, more so if you want to DIY.

I'd waste an hour on a weekend or weekday, than waste hour(s) at one dealer who's unwilling to help.

What plugs do you have? Did your original coils fail? Have them troubleshoot with O.E spark plugs and OEM coil packs. If you want to continue with the dealer. Then if they're not willing to work with you and you're within your warranty period, you could try contacting VWoA and see if they can try to do anything for you, worth a shot.

Otherwise, go to another willing dealer :lol:

Garden State Euros, I'm sure there's members in that group that can help ;)
 

12bluemk6

Ready to race!
VAGCOM is honestly needed with this car, more so if you want to DIY.

I'd waste an hour on a weekend or weekday, than waste hour(s) at one dealer who's unwilling to help.

What plugs do you have? Did your original coils fail? Have them troubleshoot with O.E spark plugs and OEM coil packs. If you want to continue with the dealer. Then if they're not willing to work with you and you're within your warranty period, you could try contacting VWoA and see if they can try to do anything for you, worth a shot.

Otherwise, go to another willing dealer :lol:

Garden State Euros, I'm sure there's members in that group that can help ;)

wow, i don't know why i didnt think to ask them. lmao.
 

Fyodor Dostoevsky

Ready to race!
12bluemk6:

Did you ever find out the cause of the rough idle problem you posted about back in 2015?

I have a similar issue with my 2013 GTI. Mine is 100% stock. During idle, normally when the engine is warm, sometimes the engine 'stumbles' every few seconds, as if a cylinder didn't fire correctly. However, sometimes the engine runs perfectly smooth as well.
 
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