STFT -35 on Both Banks LTFT 0 on both banks I am confused !!! Need some guidance

This topic has 3 replies, 2 voices, and was last updated 4 years, 7 months ago by jkreutzer.

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September 21, 2019 at 12:23 am #86617
cuyler5334
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This is on a 2000 Ford Ranger 4.0 pick up 4×4. Massive Rich condition -35 STFT and 0 LTFT I won’t have my scanner until next week could anyone point me in any direction. This should be reading the opposite right?
September 21, 2019 at 8:06 pm #86925
cuyler5334
Participant
I just might have a bad PCM
September 24, 2019 at 12:58 pm #87924
cuyler5334
Participant
Watchdd advanced fuel trims and that help answer my questions on the ltft issue. One of the upflow 02 sensors was NG. Replaced it and numbers started responding. Still have an issue on the lean side but chase continues.
October 2, 2019 at 6:59 pm #91315
jkreutzer
Participant
negative fuel trims on both banks would indicate a fuel delivery problem. stop throwing parts at the problem. Check fuel pressure. Now that you changed the O2, what are the STFT and LTFT at idle with engine hot.
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