3.0 tdi juddering / missfiring

[Lambster]

I'm asking for a friend of mine
He has a 54plate 3.0tdi Quattro auto
The problem is that whilst driving sedately or toe down there is a missfire like judder not quite as bad when cold also when stationary sometimes it just cuts out
Vag com says fuel pressure regulator but these have been tested and a new tank pump fitted
Hope anyone can help
Or this could be expensive throwing lots of new parts at it
Cheers

 

[desertstorm]

As you say you don't want to just throw money at it. Have you changed the fuel filter, cheapest and most obvious thing. If the high pressure pump has an issue then it may look like a fuel pressure regulator problem but then this is probably one of the worst case scenarios.
It is difficult to diagnose these kind of problems and they could be due to several issues.
Have you looked at the fuel pressure in real time in the measuring blocks to see whats happening.

http://www.vwaudiforum.co.uk/forum/showthread.php?80813-3-0-TDI-problem

Karl.

 

[Lambster]

Cheers for the reply Karl
He did change the fuel filter the same time the tank pump was changed
Il have to nip up to his this week with the laptop and get some logs and check the fuel pressures
I seem to remember there being a drop in fuel pressure down to 0 on idle hence the tank pump being changed
Cheers