Replace the sensor. The difference is:

-Sending unit (goes the the gauge) has only one wire.
-Sensor (goes to the computer) has two or three wires.

Since the sensor gives the computer info on the air/fuel mixture, I would fix that before I did anything else. Cleaning the MAF is always a good idea though.

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(SOLD) 2003 Ranger 4.0L V6 FX4
2001 F150 Supercrew Triton V8 (DD)
2008 Fusion 3.0L SEL V6 (my baby)
1992 Taurus SHO MTX (my toy-almost Supercharged)
2004 Nissan Murano SL AWD (Wife's car)