Volvo: hesitation & code, vacuum leaks, vacuum lines

Question
i have had a hesitation only when cold on my 1997 960 volvo and replaced several vacuum lines when the code read "secondary air flow". today the code read 'too lean bank one" and i can not find anything to explain this code. can you help me. thank you!

Answer
Martin,
Secondary air system is not the vacuum in the manifold. It is the air pump that pumps air into the exhaust and that helps heat up the cat so it begins to work. Too lean maybe the vacuum leaks. Try clearing all the code and drive the car for a while to see is any codes return. Disconnect the battery for 10 minutes to allow the control unit to return to a center position.