Cadillac Seville STS Problem Report
Cadillac Seville STS Check Engine Light Due to Intake Manifold Vacuum Leaks
An intake manifold vacuum leak can develop from a variety of sources, often causing illumination of the Check Engine Light with codes P0171 & P0174 stored. Thorough diagnoses will be necessary to pinpoint the cause in order to make the correct repairs. A "smoke" machine is often used to isolate the cause of difficult to find vacuum leaks.