[V6-12v] Tapping noise

[James4ihl at aol.com]

Hi All --

Firstly, to all those who were following my prolonged battle with a 
hesitation problem - the local garage pulled the fault codes again and once more the 
car had thrown up an intermittent lambda sensor non-signal. I'm therefore 
replacing the lambda sensors to try and cure the problem (they were at 120K, and 
well due for replacement anyway). I'll let you know if it works!

Secondly, has anyone ever experienced an intermittent tapping noise when the 
engine is up-to-temp? I know it's normal on Audis to have a little tapping 
from the hydraulic lifters (tappets... whatever you like to call them!) after a 
cold start, and that this can last up to a minute without cause for concern - 
mine tends to last about 10 seconds from a cold start, if it decides to 
manifest on a particular day. However, I've not heard of this tapping coming from 
nowhere once the engine is up to temp. It occurs intermittently and seems to 
happen when the car is being driven faster than I normally get the opportunity to 
drive it on the island where I live, which is generally low-speed windy roads, 
particularly after a hard, revving bit of accelleration. Once it does occur, 
it'll last about 2 minutes or so, regardless of how I drive, then dissappear 
again.

Is this any cause for concern? Is it still a lifter I'm hearing (sounds 
similar to what I hear in the morning on a cold start? Is this possibly just 
because I don't get to drive the car that long, or fast where I live?

Any ideas/ advice would be appreciated.

Cheers
James