2001 Cadillac Deville Left ans right banks running lean

2001 CADILLAC DEVILLE
128,000 MILES • V8 • FWD • AUTOMATIC
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RACARRAS
  • MEMBER
  • 1 POST
Trouble code PO171 and P0174 keep coming up. I checked for vacuum leaks and have changed the Mass Air Flow Sensor but every time the "Service Engine Soon" light is reset it will only go about 30 miles before coming back on. The car runs fine but at idle the engine is always hunting for the correct idle speed going between ~600 and 800rpms. Any suggestions would be greatly appreciated. Thanks You.
Mar 21, 2009 at 2:11 PM
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FACTORYJACK
  • ✓ASE Certified Mechanic
  • 4,159 POSTS
  • ASE Certified Mechanic
High probability that the plenum boot has a split in it causing a vacuum leak. The split usually occurs around the bottom, and can be a bit difficult to isolate. The boot is between the intake, and aluminum crossover.
Mar 30, 2009 at 9:55 PM
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