Check Engine Light Due to Intake Manifold Vacuum Leaks on Cadillac DeVille

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.

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Average mileage: 132,940 (11,700–187,000)
Engines affected: 4.6L V8, 4.9L V8
7 model years affected: 1991, 1994, 1995, 1996, more1997, 1998, 1999
12 people reported this problem
5 people shared problem details
Diagnostic scan check - found engine misfire due to Intake Manifold Cracked and Leaking. No work performed at this time.
2 people like thisFlag inappropiate
1999 Cadillac DeVille175,000
Cracked Intake Manifold was causing a misfire. It was Replaced with an Aftermarket Dorman intake. (Least expensive option)
Engine need servic cod#10174
check engine light comes on while driving
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