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High LTFT and P0420

  • djc7011
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1 year 10 months ago - 1 year 10 months ago #63896 by djc7011
High LTFT and P0420 was created by djc7011
2011 Acadia, 3.6, 136k.
Has P0420, +9-11 LTFT at idle both banks,  maf 3.3gps at idle, .7v both o2 #2 sensors with almost no fluctuations, .1-.8v on both #1 sensors with quick movements. No exhaust or vacuum leaks found. Visual inspection of converters is normal. I would like to fix the p0420 code and bring the LTFT down.
Last edit: 1 year 10 months ago by djc7011.

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  • Chad
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1 year 10 months ago #63907 by Chad
Replied by Chad on topic High LTFT and P0420

.7v both o2 #2 sensors with almost no fluctuations, .1-.8v on both #1 sensors with quick movements.

 
Is this true at idle and under load/highway cruising?
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."
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1 year 10 months ago #63921 by djc7011
Replied by djc7011 on topic High LTFT and P0420
Sitting in garage. No load. Cruising seems the same, o2 sensors act normal. The cats run at 1100-1400 degrees on the highway. The only thing I notice is Ltft high at idle and improves when throttle opened. This indicates a vacuum leak but I have to look harder for one. Maybe intake manifold gaskets.

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