> wrote in message
oups.com...
> Hi,
>
> I test drove a 03 vette last night with a supercharger. At low idle it
> would keep changing from about 800 RPM to 1300RPM. Up and down. I was
> this is normal for any supercharged engine. Is this normal, or there
> something wrong?
>
> There was also a fuel/mixture control. Can anyone explain how to set
> this?
>
> Thanks, Andy
>

The surging idle is not something to just glance over. I have a
supercharger on my 89 Trans Am and the idle is steady. There is definitely
something wrong. Probably a vacuum leak possibly caused by going into boost
and blowing a vacuum line off that couldn't handle the added pressure.

The fuel/mixture control is meant to keep the air/fuel ratio rich when you
go into boost. If you lean the mixture out too much, you will burn a valve
and you'll experience more problems than you already have. To set it, you
need to know a lot of information you'll probably never get. Typically one
would overly richen the mixture and slowly work down from there until the
air/fuel ratio gauge shows the mixture registers on the scale instead of so
rich, it's off the scale.