2001 Cadillac Deville Help

2001 CADILLAC DEVILLE
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KENDALLSL
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  • 1 POST
Engine Mechanical problem
2001 Cadillac Deville V8 Two Wheel Drive Automatic

Would a faulty spark plug cause the RPM's to fluctuate causing a rough idle and pull error codes p0171 and p0174?
Feb 9, 2009 at 11:58 AM
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FACTORYJACK
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 4,159 POSTS
It would not cause a lean code on both banks(p0171/p0174). I would suspect a split in the intake plenum boot between the throttle body, and plastic intake. The other possibility would be a leaking intake, or mass airflow sensor. The higher probability is the boot though.
Feb 9, 2009 at 9:41 PM
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