Suspect MAF?
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Joined: Jan 2005
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From: Dublin, OH
Suspect MAF?
From a Ford F150 TSB:
Disconnect the MAF sensor connector. This puts the vehicle into Failure Mode and Effects Management (FMEM). In FMEM mode, air flow is inferred by using rpm and throttle position instead of reading the MAF sensor. (In addition, the BARO value is reset to a base/unlearned value.) If the lean driveability symptoms go away, the MAF sensor is probably contaminated and should be replaced. If the lean driveability symptoms do not go away, go to the PC/ED Service Manual for the appropriate diagnostics.
This came up in another post the other day. Basically, if you suspect some drivability issue (rough idle, bucking, surging, missing, low power, poor economy, whatever) is caused by the MAF, unplug it. If it gets better, the MAF is probably bad. If it doesn't get better, you learned nothing about the MAF.
Disconnect the MAF sensor connector. This puts the vehicle into Failure Mode and Effects Management (FMEM). In FMEM mode, air flow is inferred by using rpm and throttle position instead of reading the MAF sensor. (In addition, the BARO value is reset to a base/unlearned value.) If the lean driveability symptoms go away, the MAF sensor is probably contaminated and should be replaced. If the lean driveability symptoms do not go away, go to the PC/ED Service Manual for the appropriate diagnostics.
This came up in another post the other day. Basically, if you suspect some drivability issue (rough idle, bucking, surging, missing, low power, poor economy, whatever) is caused by the MAF, unplug it. If it gets better, the MAF is probably bad. If it doesn't get better, you learned nothing about the MAF.