2004 Cadillac DTS

Computer problem
2004 Cadillac DTS V8 Front Wheel Drive Automatic 70,000 miles

I have a lean code. What could be wrong and how do I fix it?
Thank U
February 17, 2009.

You have a lean code for just one bank, or both? A lean code on just one bank could be O2 sensor, dirty injector, intake leak, or other vacuum leak that would only affect one side. If you have a lean code for both banks, you could have a skewed or dirty mass airflow sensor, leaking plenum, high alcohol contented fuel, an open vacuum source on the intake. Most typically, if it is both banks, the plenum boot between the intake and throttle has a split in it. This is usually on the bottom side, and can be somewhat intermittent. It can often be accompanied by a higher than normal idle speed.

Feb 18, 2009.
You are correct on the ripped boot. We changed it today and decided to change the manifold gaskets also. All better now. Thank you for your time. Peter

Feb 18, 2009.