Misfire on New 35TDI?

[Aldi-Sport Chap]

Hi all and a little help required:
Every time I get into the car with a cold engine, after about 3 miles there is a short lived hesitency/misfire at about 40mph in 5th on part throttle. If I press or release the throttle it goes away and and it only happens on a warming engine and so far only once per drive, and only for 2-3 seconds. It's fine when the oil gets over 60ºC ish. I thought it was my driving style (like miss daisy!) but it has happened with my better half and even with cruise control. If I drive straight to the dual carriageway 2 miles away and get up to 70 it is fine but if I stay on slower roads and am stuck at about 40mph it nearly always happens.
I already know what my main dealer will say, so I thought I'd ask the experts first! It's 4 months old & done 2500 miles. It has been doing this for about 400 miles now.

Anyone else had anything similar?

 

[smog c6]

You sure it’s a misfire? Any engine codes?
These cars are very advanced and can usually pick up a slight misfire.

Maybe it’s just changing the EGR valve position.

 

[Aldi-Sport Chap]

Thanks.
No I'm not sure it's a misfire. Hesitency/splutter usually only lasting a few seconds. Just once per warm up cycle. Changing EGR valve position? Maybe. If so it's slow at doing that.
No codes showing but maybe hidden in the depths of the system ready for the next service.

 

[DyslexicDog]

So you have a constant foot position at 40mph and it does a thing?

• Could it be a bump/pothole or similar that you travel over at the same time?
• Perhaps it’s between gears and it changes gear at that time and that’s what you’re feeling.
• It could also be the car transitioning out of cold mode and into normal running. I know for the industrial Diesel engines I work with and their calibration, the EGR only becomes active when warmer, so it could be that you’re feeling - not the valve but the sudden introduction of the EGR gases into the system - it’ll change combustion slightly.

Just a few thoughts.

 

[Aldi-Sport Chap]

Hi again Thanks DD for the thoughts. My afterthoughts!
No not a pothole. It happens whether I drive north, south east or west from home. Just has to be a cold start
Not between gears, it is always in D5 steady 40 ish, generally level roads and after 2-4 miles - even with cruise.
Now then, transitioning from one mode to another. This may be it. But if no one else's regularly does this then I can assume something isn't working as it should or is sticking.
Having said all that it didn't do it this morning. Maybe a transient issue now gone. I will monitor.

 

[DyslexicDog]

Hi again Thanks DD for the thoughts. My afterthoughts!
No not a pothole. It happens whether I drive north, south east or west from home. Just has to be a cold start
Not between gears, it is always in D5 steady 40 ish, generally level roads and after 2-4 miles - even with cruise.
Now then, transitioning from one mode to another. This may be it. But if no one else's regularly does this then I can assume something isn't working as it should or is sticking.
Having said all that it didn't do it this morning. Maybe a transient issue now gone. I will monitor.

I had a 1.5 TSI VW engine that I would bounce when pulling away when cold. It wasn’t on every engine and was hugely operator specific - I was sensitive to it but others weren’t.

The moral of the story is that it could be you’re tuned to the issue now and pick it up.

 

[Aldi-Sport Chap]

I had a 1.5 TSI VW engine that I would bounce when pulling away when cold. It wasn’t on every engine and was hugely operator specific - I was sensitive to it but others weren’t.

The moral of the story is that it could be you’re tuned to the issue now and pick it up.

The 1.5 with manual gearbox issue is well known, and more frustrating is that it doesn't affect every car. Not sure if VW have found the cause/cure yet. My mate's Tiguan is awful no matter who drives nor how. I drove it gently, he thrashes it, but it hesitates noticeably.

Anyway back on topic. This is far too dramatic to need to be tuned to it. It really feels like it's about to fail then picks up again. A real cough - splutter - hesitate and away it goes.

I'll try to video it next time.

 

[DyslexicDog]

The 1.5 with manual gearbox issue is well known, and more frustrating is that it doesn't affect every car. Not sure if VW have found the cause/cure yet. My mate's Tiguan is awful no matter who drives nor how. I drove it gently, he thrashes it, but it hesitates noticeably.

Anyway back on topic. This is far too dramatic to need to be tuned to it. It really feels like it's about to fail then picks up again. A real cough - splutter - hesitate and away it goes.

I'll try to video it next time.

I used the example to illustrate a similar point. It appears your issue is not that subtle.

A video would be useful, mainly for Audi.

Have you reported it yet?


Sent from my iPhone using Tapatalk

 

[Aldi-Sport Chap]

Not contacted Audi yet. I was checking to see if it was unusual, which it seems it is.
I agree a video will focus Audi otherwise my local place will just send it back to me fault not reproduced.

Having said that it's gone 2 days without an issue, fingers crossed. I'll keep you posted and thanks for the thoughts.