From: "Phil Payne" 

> > b) Regular service.  Mixture adjusted every week, OXS sensor changed
every
> > 40,000 miles, etc.
>
> Mixture?  How hard is that to do on an Audi and why does it need adjusting
> so much?  Here it's all handled by computer and it would be a total pain
> (time and cost-wise) to do anything every week.

Takes about ten minutes.  Rpm meter (Draper DMM5) on the coil low tension,
Gunson Colortune in #1 plughole, long 3mm Allen key and a flat-blade
screwdriver.  It's part of a eneral regime of listening to the engine and
looking round the engine bay for leaks,etc.

Most computer systems set mixture and idle against tables, making no
allowance for volumetric efficiency changes caused by wear.  When I go in
for the mandated annual emissions tests, I often get a couple of monkey
boys looking at the printout and the vehicle mileage and shaking their
heads.

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