Peter Grey wrote:
There are a lot of things that could cause your problem. The first thing I
would do is go to your local parts store and get a code reader. They're
cheap (the last one I bought was like $19) and it'll translate the code(s)
that are causing the check engine light to go on. Most code readers come
with a book that'll tell you what the codes mean.

Actually, I think you can read the code by jumpering two terminals on
the diagnostic plug under the hood. Then you turn the key to on, and
it will blink the codes on the check engine light.

They may also have a diagnostic procedure that can be triggered by
a sequence of manipulating the key and the gas pedal. Something like
turn key on, press gas pedal to floor, turn key off, release gas pedal
and turn key to start. It runs a 2-minute test sequence that ramps
engine speed up and down, disables one bank at a time to check the
oxygen sensors and a bunch of other stuff. When done, it will report
a different set of codes.

I got the Audel's book, but their interpretation of the codes was all
wrong! It called out stuff that was totally unrelated to the problem,
so I ended up having the dealer fix it for an outrageous cost.
So, you might check around to see if somebody has a list of fault codes
that is known to work for this engine any year.

Jon