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?
Monday, February 9th, 2009 AT 11:58 AM
1 Reply
FACTORYJACK
MECHANIC
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.