1995 Audi A6 Quattro Q&A

1995 Audi A6 Quattro Question: why does check engine light come on in town,but not on interstate?

lower speeds and rpm light comes on.Higher speed and rpm will stay off until I reduce speed to 2000 rpm. -
Answer 1
Scanner can answer that one,have test performed. -
Answer 2
HAVE CODES SCANNED AND POST ITS COULD BE SEVERAL ISSUES -