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Car stuttering at low revs

Posted: Thu Mar 25, 2021 10:16 pm
by Athers
Hi all,
My 2015 car (57k miles, no mods) is stuttering at low revs (1500-2000 rpm) on a light throttle load.
No loss of power - pulls fine, never does it with the box in sport - (presumably because it’s never that low down in the Rev-range)
Not showing any fault codes, not doing it whilst it’s flicking in/out of cylinder deactivation.

Dealer had it in twice and can’t diagnose the issue and it’s now driving me nuts.

Anyone suffered the same/got any suggestions?

Thanks

Re: Car stuttering at low revs

Posted: Fri Mar 26, 2021 12:29 pm
by Saudirick
Has it had a service lately? Surprised its not showing any misfire errors

Re: Car stuttering at low revs

Posted: Fri Mar 26, 2021 12:47 pm
by Athers
Was serviced 6000 miles ago. Had had a fuel system cleanse and oil change since which has made no difference

It doesn’t feel like a misfire - and it goes away above 2200 rpm and pulls smoothly all the way through to the red-line

Because the OBD shows zero faults the Audi mechanics can’t tell me what it is - I’ve left them with the car, told them to give it to a mechanic to drive until they find out what it is.
My concern is that they start tearing down the engine at huge labour cost without knowing what they are looking for

Re: Car stuttering at low revs

Posted: Fri Mar 26, 2021 3:41 pm
by Saudirick
Does it tick-over fine? Have you tried it without the air filter in? I would suspect sparkplugs but I am just trying to think of the things I would look for in the situation. An air leak would cause stuttering when pulling away from tick over, a vacuum leak can can the symptoms you describe. Is it worse when cold or hot? Can you re-create it without actually driving the car - i.e, increasing the revs in neutral? The dealer should check the emissions

Re: Car stuttering at low revs

Posted: Fri Mar 26, 2021 4:20 pm
by Athers
Ticks over fine - revs cleanly in neutral.
Only does it on a steady throttle - usually 8th gear around 60mph - not when pulling away from tickover. When it’s sputtering the rev counter is stable.

Haven’t tried taking the air filter out.

The weird thing is that it ONLY does it between 1500-2000 - anything above that there’s absolutely no problem.

Re: Car stuttering at low revs

Posted: Fri Mar 26, 2021 11:13 pm
by Tadass910
You mean rpm arrow jumping between 1500-2000 rpm ?

Re: Car stuttering at low revs

Posted: Sat Mar 27, 2021 6:36 am
by SasaRS6
If i understand you good, i have same problem, some kind of lag but when you press throtles milimeter more, no problem at all. I didnt start to investigate what it is.

Re: Car stuttering at low revs

Posted: Sat Mar 27, 2021 9:31 am
by Simeix
Is this not when it switches between 4 and 8 cylinder modes?

Re: Car stuttering at low revs

Posted: Sat Mar 27, 2021 2:32 pm
by Athers
Tadass910 wrote:
Fri Mar 26, 2021 11:13 pm
You mean rpm arrow jumping between 1500-2000 rpm ?
No - the tacho doesn’t fluctuate at all when it’s happening

Re: Car stuttering at low revs

Posted: Sat Mar 27, 2021 2:32 pm
by Athers
Simeix wrote:
Sat Mar 27, 2021 9:31 am
Is this not when it switches between 4 and 8 cylinder modes?
Not according to the display

Re: Car stuttering at low revs

Posted: Fri Apr 09, 2021 11:18 pm
by Jimy
Hi Athers,

I have similar problem. Started few weeks ago. Stuttering in aprox. 15% of throttle in comfort few km after the start. First impression that the problem could be in the gear box or some kind of "fuel cut". Brought the car to dealer to find out the problem . Diagnostic showed misfire in 3 and 4 cylinder. My biggest problem that this comes not every time , I have this issue only if the car stays more then 24hrs and even then it lasts for a very short time. So result is the same - dealer can't identify the problem. As my car is on the stage 2 dealers explanation that this could be because of the remap issue, sparkplugs or VANOS- although my car has now 42k km I did stage 2 when car had 25k and until few weeks ago I didn't have any problems so I really in a big doubt that the problem could be in remap. Dealer tried to explain me that this is not a big problem and I can live with it but telling the truth for me this sounds stupid especially when the feeling of this stutter is quit hard and annoying.

Re: Car stuttering at low revs

Posted: Sat Apr 10, 2021 2:37 pm
by Tadass910
Jimy wrote:
Fri Apr 09, 2021 11:18 pm
Hi Athers,

I have similar problem. Started few weeks ago. Stuttering in aprox. 15% of throttle in comfort few km after the start. First impression that the problem could be in the gear box or some kind of "fuel cut". Brought the car to dealer to find out the problem . Diagnostic showed misfire in 3 and 4 cylinder. My biggest problem that this comes not every time , I have this issue only if the car stays more then 24hrs and even then it lasts for a very short time. So result is the same - dealer can't identify the problem. As my car is on the stage 2 dealers explanation that this could be because of the remap issue, sparkplugs or VANOS- although my car has now 42k km I did stage 2 when car had 25k and until few weeks ago I didn't have any problems so I really in a big doubt that the problem could be in remap. Dealer tried to explain me that this is not a big problem and I can live with it but telling the truth for me this sounds stupid especially when the feeling of this stutter is quit hard and annoying.
If this happens only occasionally maybe you can live with that, maybe fuel to good who knows, I think problems can be more serious if you have engine light on and after deleting codes they could appear right away, also I imagine that dealers don’t want to put hands on remaped cars, that’s true, I got also some time check engine with code p2196 o2 sensor signal biased/stuck rich bank 1 sensor 1 and Audi changed sensor and nothing helped from time to time I still get it 2-3 times a year, I delete code and drive, I don’t feel any side effects, audi said it can be because of fuel

Re: Car stuttering at low revs

Posted: Mon Apr 12, 2021 10:33 am
by Jimy
Finally found the problem - it appears that left turbo is coming to an end....so ask dealers to check both turbo.

Re: Car stuttering at low revs

Posted: Mon Apr 12, 2021 12:48 pm
by Athers
Turbo done at 42k?!
That’s not good news - dealers have had mine for 3 weeks now and still no diagnosis

Re: Car stuttering at low revs

Posted: Mon Apr 12, 2021 1:36 pm
by Jimy
No good at all, aspecially when 3k km trip is planed for next week. Good news if it's allready happened I will go for TTE 800 upgrade turbos. But anyway biggest problem that turbos are the result of the problem. We need to find out who coused this issue after such a short time.l. But by words of the dealer it's quit ussual when turbos does not last more then 50k km in stage 2.