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.
Check Engine Light Due to Intake Manifold Vacuum Leaks on Cadillac Seville
Average mileage: 76,000 (76,000–76,000)
12 people reported this problem
1 person shared problem details
1998 Cadillac Seville76,000Visitor
engine needs service soon
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The crankshaft position sensor may fail causing the engine to stall intermittently, the Check E...
The EGR valve may stick open, causing a rough idle and/or the Check Engine Light to illuminate.