Lumpy RPM (small range)

[Arnie2007]

Hey guys.

Just a little question: I have a 2007 B7 2.0TDi BRE. 82k on the clock.

It's had a little judder when cold since owning it between 1800-2000 rpm. It's only when cold though, once the car has warmed up it doesn't do it. When pulling away it can make the car 'kangaroo' through those 200rpm. Up to 1800 and after 2000 it's fine.

I also notice that when cold, if I sit in the drive, leave it in neutral and rev it slowly through the range, when I get to the 1800 - 2000 mark and hold it there the car vibrates ever so slightly (as in I can feel it through the steering wheel).

I have popped some EGR cleaner through the system as it is an 'around town' car but this hasn't made any difference.

I don't want to sound like an arrogant git, but I'd be interested to hear if anybody has experienced anything similar, not replies along the lines of 'could be this, could be that, gonna cost ££££'s' lark. I know thats the point of a forum but sometimes people get carried away. It has been plugged in and scanned at the local Audi dealership and the car returned zero faults (they done a full sweep, but it wasn't regarding this issue). I've since had it scanned at a local garage (where I have my service), they too reported zero fault codes.

I'm no stranger to getting hands on, but I'd rather have an idea of what to tackle than spend loads of time pulling loads of things apart: I've got a newborn baby so time is at a premium (actually, as is sleep ).

So, any thoughts at all?
Cheers!

Dan

(NB-I know the post reads really miserable, but it's not like that I promise!).

 

[SDHA4SLine]

I doubt you'll get any "it'll definitely be this" answers, only answers you don't want which is ideas/suggestions from us armchair mechanics.

So with this in mind I wont aggravate you with a guess

 

[SootySport]

That kind of problem could be lot's of things from air leaks, injector problems, temp. sensors, I could go on. But as young Steve says, it's never that simple to diagnose when the scan tools won't show up a definite fault code.
If I were you I would take the car to a VAG independent specialist near you, there are some real clever engineers around who are more Au Fait with our cars than a Main dealer. Have a look at our own forum for someone local to you - http://www.audi-sport.net/xf/categories/site-sponsors-and-banner-advertisers.111/
If your in the South East your lucky, as AMD are by Lakeside Shopping.

 

[Arnie2007]

To be honest-i put about the guessing because from experience, people tend to jump in with their own horror stories that ultimately end in 'which cost me £££'s'. I'm not saying thats the case all the time, but I wondered if anybody had experienced the same at any point, whether it was a small part of a bigger problem or just something quite simple.

Of course I'm open to suggestion, perhaps the post didn't read very well: I just want to avoid 'extreme' catastrophic responses without factual evidence to back it up.

With regards to locality, I am Easterly but still 120 miles the wrong side of AMD. I do frequent Lakeside IKEA occasionally though so if I head that way before christmas and the problem is still present then I'll pop my head in.

Thats the difficulty I've had so far, two 'clean' scans, one of which was Audi, which has made me think perhaps it's something quite simple that I may be overlooking; as surely something quite big would have shown up.

I tried the EGR cleaner because I thought perhaps it may have been the valve opening but being built up with crud so the air couldn't pass through. Then I thought injectors because maybe they're struggling with fuel delivery when at a certain work rate: I know a local garage that can perform an injector flush-but thats upwards of £100, may not cure it, and could end up causing more problems. I'm trying to look at cheap/DIY solutions first as I've just spent £460 on new tyres and really brakes need to be next.

I thought maybe someone may have encountered this or similar before in an attempt to find a path to kangaroo enlightenment!

 

[mm707]

Mine has been like this for ages, still did it after a new set of injectors so doubt the injector flush would work

 

[Arnie2007]

Did you try anything else? Like cleaning the EGR valve either with a fluid or removal/clean?

 

[mm707]

It's had a new egr valve about 4 years back. About a year ago I cleaned it out and also removed the inlet manifold to change the actuator. Whilst that was off I cleaned all the gunk out of that too.
Still has a lumpy idle especially when cold and sometimes does the kangaroo take off.

I was getting hesitation at 1600 - 2000 rpm, changing the actuator on the inlet manifold cured that. They have a diaphragm inside which splits, only costs about £10 and easy enough although you have to remove inlet manifold but if I can do it anyone can.

 

[soldier4313]

Don't suppose you'd be willing to tell me how you did this as mines just gone and Audi want £400 to fix