Hello everyone, first of all, sorry for my English because it is not my native language. 

Now to my problem. When I cold start my car, everything is ok, but when the engine is warm and rpms immediately go to idle, engine starts to run rough, like it would stall in any second. This rough idle lasts for maximum of ten seconds and then the engine runs smoothly, also rpms do not jump up and down. Also when I shift from P to D, it shows D1 on maxidot but when I release the break it jumps from D1 to D. It seems to me like the dsg is disengaging the clutches because otherwise it would stall the engine. I've already changed N205 magnets/solenoids but without any success and the problem is still there. I also had the car on VCDS diagnostics which shows zero fault codes related to the engine or gearbox. 

 

Thanks in advance for any tip that could help me 🤞.

 

What is the mileage of the vehicle?  Intermittent rough running would be something like: spark plugs or the coils breaking down when getting warm.  Check out the misfire counters; if you have a high number of misfires, then its time to look at new sparkplugs and coils (all 4).  If the crank position sensor is failing, then it should show up a fault or there was an issue with the O2 sensors, again a fault would be shown.  Typically, every change sparkplugs every 50k miles/84k kms depending on driving style and definitely replace coils every 100k miles/160k kms.

It has 170k km and the spark plugs has been changed like a month ago. But still no fault codes on the diagnostics. 

What are the misfire counters like?

Checked the misfire counter today and there are zeros on all four cylinders.

@varaderoguy So i found out, that i might have a vacuum leak, because when i remove oil cap while engine on idle i hear very loud a strong suction and engine rpms go up. Already changed pcv valve with oem part, but the problem is still there. 

If it's a PCV valve then the car will throw an error. Any chance you can get a scan done?

Still no error codes 😕

 

It’s rough idle but no misfire counters at all? Normally even a smooth idle will produce a few especially when cold?

 

If that’s really the case I’m thinking more a physical issue, like engine mounts, dog bone mount, dmf,  maybe v  belt issue with crank pulley or tensioner.

I think there was a tpi on the harmonic balancer/ crank pulley re vibrations if my recall is operating correctly!! 

 

Re v belt, carefully observe when engine idling maybe remove belt. Care With hands and running engine required. Don’t wear a tie either when checking! 

@TheClient What do you think about those cold starts, when my car works perfectly? 

3 hours ago, Digger23 said:

@TheClient What do you think about those cold starts, when my car works perfectly? 

Dont know what to make of it. Put up until it gets worse? It's not always the best advice but fault finding if you've ruled out all the obvious can be very hard to pin down on something like this. 

 

Is it your feeling that the engine is misfiring. On live data you should see it if it is..