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.
Problems for specific Cadillac Seville STS years:
Car problem reports
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Most reported 2000 Cadillac Seville STS problems
The steering wheel position sensor may fail, resulting in the service stability message being displayed.
A Loose or worn gas cap may cause Check Engine Light to illuminate.
The steering may develop a clunk type noise from the upper intermediate steering shaft. Our technicians tell us that you should check with you local GM dealer to find out what the latest repair is for this condition.