Skoda Octavia VRS - Rough Cold Running

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Wed 19 Sep 2012 23:20
Skoda Octavia VRS - Rough Cold Running - Steve33

I have an 07 plate petrol VRS with 72k on the clock. Recently it has started to run roughly when the engine is cold. At idle it is best described as a slight misfire which can be felt in the cabin. When driving it is hesitant between 1750 and 2500 rpm but clears when it gets out of this rev range. It is run on Shell fuel.

It has been to my local VAG independant garage for diagnosis. No fault codes were logged and real time data was within expected normal parameters.

Any ideas on where to go with this next?

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Mon 10 Dec 2012 22:10
Skoda Octavia VRS - Rough Cold Running - elekie&a/c doctor

I was not convinced the cam sensor was the fix.Fsi engines are now emerging with poor idle and lacklustre performance.This is often caused by the air inlet path behind the inlet valves being blocked with crankcase oil/breather sludge.The set up of an Fsi engine means the injector sits below the inlet valve ,so there is no fuel wash behind the valves to keep the air passge clear.I would suggest the inlet manifold be removed for inspection of the airway.It may also be a good idea to get the injectors removed for cleaning and flow testing while the manifold is off.If you do decide to get the injectors out,make sure the person doing the job has the correct tools to renew the seals ,as they are single use only.hth

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Wed 19 Sep 2012 23:42
Skoda Octavia VRS - Rough Cold Running - unthrottled

I'd take a guess at coolant temperature sensor or air intake temperature sensor. A short circuit on either would appear to the ECU as a hot engine/hot hot ambient conditions which would reduce enrichment at idle-giving rise to lumpy idle. Under load, the engine is most sensitive to coolant and air temperature in the 1750-2500RPM range because this is the range where detonation is usually most likely. Disconnect each sensor and see if the symptoms are reduced (no data is better than faulty data!).

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Thu 20 Sep 2012 13:21
Skoda Octavia VRS - Rough Cold Running - willingtonsteve

I had this problem on my Octavia VRS, turned out to be the Coil pack.

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Thu 20 Sep 2012 13:28
Skoda Octavia VRS - Rough Cold Running - unthrottled

Coil packs usually go the other way, fine from cold but get worse as they warm up.

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Fri 21 Sep 2012 14:31
Skoda Octavia VRS - Rough Cold Running - Steve33

Thanks very much for the suggestions.

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Fri 21 Sep 2012 23:23
Skoda Octavia VRS - Rough Cold Running - Crasher

This is something that affected the Octavia 1 with the AUQ engine but not the Octavia 2. I am puzzeled as to why no fault codes are stored.

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Tue 27 Nov 2012 21:14
Skoda Octavia VRS - Rough Cold Running - Steve33

Update - The car has been back to the garage. Apparently coolant temp sensor was providing a different temperature to actual. Sensor has been replaced.

Problem still exists. Still hesitant etc as before. Car now doing 26-28 mpg instead of its usual 34 ish over mixed roads. Think this is partially weather related as it usually drops a bit when its colder but not this much!

Car is booked in for a return visit next week. Any suggestions?

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Tue 27 Nov 2012 21:36
Skoda Octavia VRS - Rough Cold Running - elekie&a/c doctor

Can you supply the engine code.Is this an Fsi type motor?

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Wed 28 Nov 2012 20:01
Skoda Octavia VRS - Rough Cold Running - Steve33

It is the TSFI engine. Engine code BWA.

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Thu 29 Nov 2012 15:59
Skoda Octavia VRS - Rough Cold Running - Crasher

That sounds like a faulty cam cover breather vakve but this tends to genertate a few fault codes.

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Sat 8 Dec 2012 21:26
Skoda Octavia VRS - Rough Cold Running - Steve33

The return visit to the garage threw up a code suggesting it was the cam sensor at fault. This has now been replaced and hopefully is now sorted.

The final comment from the garage was that if this hasn't sorted things then the next suggestion was that the "timing had slipped".

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Mon 10 Dec 2012 21:46
Skoda Octavia VRS - Rough Cold Running - Steve33

Ok, so I drove it from cold this morning - still has same symptoms.

Not wanting to continue to throw parts at it, does anybody else have any ideas? Could it be that the" timing has slipped"?

The current VAG Indy garage seems to be suggesting that I return to the garage that did the belt and pump change 15k ago (main dealer) as it's their problem!

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Mon 10 Dec 2012 22:10
Skoda Octavia VRS - Rough Cold Running - elekie&a/c doctor

I was not convinced the cam sensor was the fix.Fsi engines are now emerging with poor idle and lacklustre performance.This is often caused by the air inlet path behind the inlet valves being blocked with crankcase oil/breather sludge.The set up of an Fsi engine means the injector sits below the inlet valve ,so there is no fuel wash behind the valves to keep the air passge clear.I would suggest the inlet manifold be removed for inspection of the airway.It may also be a good idea to get the injectors removed for cleaning and flow testing while the manifold is off.If you do decide to get the injectors out,make sure the person doing the job has the correct tools to renew the seals ,as they are single use only.hth

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