Stuttery / Jerky engine at 1100-1400rpm when cold!!?? Help!

[Tigger]

Hey all!

My 2012 VRS has developed an issue that has perplexed me and several mechanics.
Your help or ideas would be greatly appreciated please!

At any temp below the magic halfway 90 degrees, the engine stutters and coughs at the rev range of 1100-1400 rpm...

I noticed it particularly in slow traffic such as going at 40kph through a school zone.

We have checked and swapped over coil packs.
We have replaced the PCV valve assembly.
We have performed a full DSG service.

No error codes appear....and the issue goes away when warm (90 degrees or more)

Help!

Any ideas?

Thanks

[woofy]

I was going to say we saw a minor version of that and it was the PCV valve. Any chance it's the divertor valve as it's also know to fail, but would imagine it would cause loss of power more than a stutter. Seems like something in the EGR system isn't working right. Our PCV failing actually also threw an appropriate error.

[blower]

Cold start misfires? - sounds like the infamous carbon buildup on the intake valves & tract which is prolific on 2.0 TSI engines with as low as 40k miles. How many miles on your engine?

It may be worth checking how dirty the throttle body is and giving it a clean (and recalibration via vcds) before dis-assembly of the intake manifold and the labour intensive cleaning of the valves.

[Martin]

+1 for carbon build up in the inlet

Or a clogged injector - throw some injector cleaner into the tank, if it does not help then clean the inlet

[zei20t]

you swapped the coilpacks, but did you check the plugs while you were there?

they probably need replacing. and yes you probably have carbon build up on the intake and the stalling means your throttle is probably choked up too.

[Tigger]

Ok thanks guys!
I'll follow your suggestions!

Thanks again.

[donweather]

Cold start misfires? - sounds like the infamous carbon buildup on the intake valves & tract which is prolific on 2.0 TSI engines with as low as 40k miles. How many miles on your engine?

It may be worth checking how dirty the throttle body is and giving it a clean (and recalibration via vcds) before dis-assembly of the intake manifold and the labour intensive cleaning of the valves.

Yep agree with this also. Had the same thing on our 2009 foggy after 80,000kms. Cleaned intake manifold of all carbon and car runs like a dream now.

[readerr0r]

I don't wanna snatch the thread but my Mum's MK2 118TSI (1.8T) Elegance is very lumpy when starting up, it makes the whole car shimmy slightly while warming up. Would that be the carbon intake issue? Whats the going price for it?

It has 90K on the clock

[dArK5HaD0w]

how hard is it to do an intake manifold clean?

mine stutters to a stall once in a blue moon when coming to a complete stop in heavy start stop traffic.

sounds like have carbon build up too.
about to hit 95k.

[gamcem]

+1 to carbon build up. This happened to ours and after mechanics spending weeks 'discussing the issue' with Skoda they pulled it apart and cleaned. Has run fantastic since.. I've always wondered whether it's fuel related or potentially our driving. We only do short km's up here in Darwin and mostly under 100km/h. The car has always had 98 except for the trip from Brisbane to Darwin.

Good luck with the fault!

[Martin]

Mum's MK2 118TSI (1.8T) Elegance is very lumpy when starting up, it makes the whole car shimmy slightly while warming up. Would that be the carbon intake issue? Whats the going price for it?

It has 90K on the clock

Those are the symptoms - can happen as early as 80k but common around 90k~100k
Can cost $350~$500 to get it cleaned up

[Martin]

how hard is it to do an intake manifold clean?

mine stutters to a stall once in a blue moon when coming to a complete stop in heavy start stop traffic.

sounds like have carbon build up too.
about to hit 95k.

That sounds like something different

It's a real pain cleaning the inlet (with some risk)
Best to a workshop with things like a walnut blaster and associated tools

[Martin]

I've always wondered whether it's fuel related or potentially our driving. We only do short km's up here in Darwin and mostly under 100km/h. The car has always had 98 except for the trip from Brisbane to Darwin.

It's because the engine is direct injection into the cylinder
Normal fuel injection is into the inlet - the fuel washes the inlet clean

[zei20t]

It's because the engine is direct injection into the cylinder
Normal fuel injection is into the inlet - the fuel washes the inlet clean

^^^^ This

also, the PCV valve passes plenty of oil to coat the intake piping and throttle body

[gamcem]

Thanks for the info!