Used an O2 spacer. P0420

Tiny
DC70
  • MEMBER
  • 2005 BUICK LA CROSSE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 207,000 MILES
Car has been well maintained with records. I got a P0420 code. Ran a couple treatments with Cataclean. P0420. Used an O2 spacer. P0420. Replaced O2. P0420. Replaced Catalytic converter. After ~120 miles, P0420. I'm Stumped!
Saturday, October 18th, 2025 AT 11:52 AM

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