Hunting / erratic revs on deceleration

Madmanzippy

New Member
Hi there, i have just purchased a 2007 a6 2.0 tdi. I have replaced the throttle body with a new one as it was bad. I have strange behavior with revs when i am slowing down and the revs get down to about the 1200rpm mark. The car kind of surges or hunts till i come to a stop. Any ideas? Also the car idles at about 900rpm is that a bit high? Thanks in advance.
 

NHN

Retrofitter - Audi - VW - Skoda - Seat
Site Sponsor
VCDS Map User
Not sure on your chassis, but was there a diagnostic adaption required for the new throttle body?
 

Madmanzippy

New Member
It is an a6 c6 4f2. Didn't do any adaption, just bolted on. I only have a elm327 obd2 adaptor. I guess I will take the car to a workshop to get them to check it out. Having just moved to the uk last week i don't know who can be trusted other than my brother inlaws mechanic, but that is 100 miles away. We are currently in Shrewsbury if anyone can recommend someone.
Cheers
 

Madmanzippy

New Member
Ok, a bit of an update. I stopped in to see my brother inlaws mechanic and he checked the new throttle body and reset it or what ever and said it was fine. He checked the breather on top of the rocker cover and initially thought it may be faulty because when he unplugged the hose, there was no real change in rpm. However after checking a bit more, he seemed satisfied this was not the problem. When he had his unit plugged into the car he did notice a couple of cylinder not giving a correct ??? reading and suggested it could be the swirl valves. We have pulled the inlet manifold off and checked the valves are ok and the vaccuum diaphram is good. We also gave the manifold a good clean whilst in there. Problem still remains though. Could it be the egr? It is switching, via the mechanics tool, but that was either on or off. As this is happening just between 1200 and 1750 rpm maybe it is when it is meant to be partially open.
The car kind of feels like a manual when slowing and you forget to press the clutch. But just not as severe. If I drive like a mad man and slow quickly, you don't notice it, however I am using this as a family car and the family tend to complain when I drive like that.

Thanks
 
Top