Getting a bad mass air flow reading when I run a diagnostic test

FIXNMYFORD1993

MEMBER
1993 FORD EXPLORER
4.0L
V6
4WD
AUTOMATIC
150,000 MILES

I get codes 157 and 159 when I run a diagnostic check on my 1993 Ford Explorer XLT 4.0 v6 4x4. Code 157 is mass air flow sensor fault, low voltage and code 159 is mass air flow sensor fault, above or below normal but when I checked the voltage with my multimeter they all read normal. What else could make it give a false bad MAF sensor reading? The problem I'm having is while I'm giving it gas it will drive fine and then all of a sudden it will choke out and if I don't let off the gas it will cut off but if I do let off of the gas it will go back to idling fine but sputter when I push the gas again. It will do that for a while then run fine for a few miles then start choking and sputtering again. Can someone please help me? I desperately need answers and solutions. PLEASE!

Tuesday, April 1st, 2014 AT 3:43 PM

1 Reply

CARADIODOC

MECHANIC
34,206 POSTS

Sounds like you have an intermittent problem and you checked the voltage while the problem wasn't occurring. Also, Ford likes to be different than everyone else. You can't read the voltage on the mass air flow sensor. You have to read the frequency.

The logical suspect is the sensor, but if you want to check it first, you'd need to drive the vehicle with a scanner to view live sensor data. Thank goodness for fault codes with intermittent problems so you know where to look. Be sure to check the wiring to the sensor too, particularly the terminals in the connector.

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Tuesday, April 1st, 2014 AT 6:01 PM