Surging. I think.

[ScottD3]

Car: 3.0TDI D3 on a 06 plate

Its only been doing it the last couple of days and not all the time.

Travelling along the road and x speed, no issues, not a problem.
Come to a hill or anything that’s enough for you to take your foot off the throttle coast.
The revs normally drop to between 1000 rpm or 2000 rpm and the needle will jump about 1-200 rpm up and then back down, then up and then down again.
Its just like you’re tapping the throttle with your foot causing the car to surge forward and each blip.

Its more noticeable in 3rd, 4th and 5th and mainly when its cold or warming up.
It will do it a little bit when up to temp but no where near as bad.

The first scan I did of the car reported these two faults.
005658 - Glowplug for Cylinder 1 (Q10)
P161A - 001 - Open Circuit

001025 - EGR System
P0401 - 002 - Insufficient Flow

But they never came back after the 2nd scan.

I will scan the car when the weather holds up now that I’ve been driving it for a few more days.

Anyone got any ideas on what to check or change?

[mannyo]

That sounds like the torque converter is dropping out of lockup and back in again rather than anything else. You could try scanning the auto transmission rather than the engine to see if anything is recorded there.

The torque converter issue was a fairly common issue on the D2, but the next step after that was usually transmission failure. Do a search for A8 transmission thump.

[ScottD3]

Don't say that!!
I can't have this box going.
That's why I broke the A4 cause the box failed.

I'll do a full scan and see what comes up. I've not seen any codes for the auto box coming up.

Worse case, if it is the TC, I assume a new TC is needed and a box service won't help?

[sarg]

have you recently filled up with a different brand of fuel?

[ScottD3]

Originally Posted by sarg

have you recently filled up with a different brand of fuel?

That I have.

When I got the car it has less than quarter of a tank in it.
I then filled up with Sainsbury's and I can't remember or noticed it doing it then.
Then put Texaco fuel in on friday.

[sarg]

could be as simple as that then.

Mine runs like a bag of spanners if I put Shell Nitro in it, but loves Tesco Momentum

[ScottD3]

I'll keep an eye on it. I got a full tank of the stuff, so I hope it sorts it self out.

Normally fill up at Tesco and the old A4 has been fine but that thing could run on any thing.


Reading some other threads about tiptronic issues and some has had gearbox software updates from Audi and that has solved issues from snatching in first when pulling away to hard shift from 2nd to 3rd.

That all seems fine for me but I wonder if there is a update.

[ScottD3]

I don't think its the diesel.
It seems to be a bit harsh getting out of 1st or into 2nd.

Tempted to get the gearbox serviced as its on 155k.

[ScottD3]

Got my passenger to take a little video this morning.

This is what its doing (Mute the audio).

https://www.youtube.com/watch?v=ZJHOenQ1u-k

[mannyo]

That's weird, but it does look like the torque converter is dropping out.