Yes. Please ...Watch the Brief Video from ScannerDanner in Post #155 .
The PCM will continue reading from the Old LTFT History as remaining High from what has previously been stored in the Computer and begin to use the newly setting Negative STFT Levels to gradually counter-balance the elevated LTFT while it is in the process of "Re-learning" what the Nominal Fuel/Air Mixtures should become while Idling and through periods of Acceleration.
If you follow ScannerDanner's suggestions for how to Test this, after borrowing a Friend to do the Driving with YOU in the Passenger Seat, start out on an Empty, Safe Street from a Stopped position and Go to Wide Open Throttle in First Gear...
(Go Carefully Though... Tell the Driver to Avoid Over-Revving The Engine).
You will want to observe your Live Scanner for LTFT AND STFT as well as BOTH O2 Sensors. You should be looking for your Upstream O2 Sensor to STAY RICH while also watching that your Fuel Injector Duty Cycle increasingly ADDS FUEL. If the Upstream O2 Sensor remains RICH for that entire brief period of WOT... then you will have properly cleaned and have a working MAF Sensor again and the problem of the P0171 should then remain resolved.
The PCM will continue reading from the Old LTFT History as remaining High from what has previously been stored in the Computer and begin to use the newly setting Negative STFT Levels to gradually counter-balance the elevated LTFT while it is in the process of "Re-learning" what the Nominal Fuel/Air Mixtures should become while Idling and through periods of Acceleration.
If you follow ScannerDanner's suggestions for how to Test this, after borrowing a Friend to do the Driving with YOU in the Passenger Seat, start out on an Empty, Safe Street from a Stopped position and Go to Wide Open Throttle in First Gear...
(Go Carefully Though... Tell the Driver to Avoid Over-Revving The Engine).
You will want to observe your Live Scanner for LTFT AND STFT as well as BOTH O2 Sensors. You should be looking for your Upstream O2 Sensor to STAY RICH while also watching that your Fuel Injector Duty Cycle increasingly ADDS FUEL. If the Upstream O2 Sensor remains RICH for that entire brief period of WOT... then you will have properly cleaned and have a working MAF Sensor again and the problem of the P0171 should then remain resolved.
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