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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Before I tried to smog my 1999 Blazer, I but a new catalytic

Customer Question

Before I tried to smog my 1999 Blazer, I but a new catalytic converter purchased on line. The test passed but the visual didn't because the number on the cat didn't start with a D. I replaced it with the correct one ,drove it and the engine light came on.It failed the next test due to PO171 system too lean Bank 1 . I changed the O2 sensors and the engine light still comes. Any ideas ??????
Submitted: 1 year ago.
Category: Chevy
Expert:  JOHN aka Eauto replied 1 year ago.

lean codes are usually not o2 sensors they are usually vacuum or intake leaks...have you tried restting the light and performing a drive cycle?