Juddering on part throttle

[Tony2327]

Hi all 

After your thoughts please, I have a 2017 A6 3.0 Bi tdi that's developed a slight stuttering on part throttle. 

It seems to be slowly getting worse.

The issue seems to be only when on slight throttle held at the same revs, the car seems to stutter as if struggling for power or even fuel! 

When given bigger throttle inputs it's fine and pulls well. Car has done 65k with FSH.

I'm wondering whether it's any of the following, dirty/clogged DPF (warning light has come on 2-3 times over the past 6 months each time a good blast clears it), a swirl flap problem, a clutch problem?

 

Anyone experienced anything similar would love to hear how you sorted it. 

Thanks 

[Steve Q]

Id recommend a diagnostic check to see if any fault codes flag up. Could be a dpf but could equally be a maf sensor. 

[Autoquip]

Hi did you resolve your issue? I have the same kind of problem with my 2.0tdi ultra. However I’ve had no dpf light or engine management light and no fault codes either. 

[Sid2020]

Had similar on my car with no fault codes for While, eventually got worse and  thru a glow plug fault. Replaced them and now all is fine again, 

glow plug failures only effected  vehicle starting years gone by but on the latest generation of diesels they seem to play a bigger role due to regenerations and strict emission standards 

[Autoquip]

Hi mate, yeah you’re spot on about the glow plugs playing a bigger part in modern engines and truth be told I haven’t checked them. Might look at them if the fault is still there, cheers for the info 👍

going to post an update in another message. 

[Autoquip]

So the update….

last night I eventually got round to replacing the crank sensor. I’d like to take this opportunity to thank the team of designers for putting the crankshaft sensor in the most awkward place. 
 

however I got it done and will just have to wait and see if it’s a fix or not. I will keep you all informed in the coming days. 
 

top tip if anyone is going to try this at home. Don’t mess around trying to unplug the sensor. Take the bolt out (it’s held in the sensor so shouldn’t fall out) then unplug the sensor when you take it out. Fit the new sensor and then plug it in. 
 

myself and one of my mechanics both had a go at unplugging it but it’s not easy to get to. Now that I’ve done one I reckon 20 minutes would change it but it’s always easier the second time round. 
 

 

[Sid2020]

Hopefully that’s it’s sorted