2003 Montana - Code P0102 runs like poop

lucid

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Hi,
I have a 2003 Pontiac Montana that has been displaying a few trouble codes

P0102 - Maf sensor signal wire low
P0128 - coolant below normal temperature
P0442 - Evap vent solenoid

The car is really hard to start sometimes and will drive with no power at all. You press the gas and it tries to take off but it has no acceleration. Every once and awhile it will drive fine and take off like normal. Every once and awhile it will jerk ever so slightly instead of accelerating.

I checked the fuse #21 (underhood) and it had continuity and 14V running across the terminals. The large 40amp #5 fuse had 14V going across. Inspecting the wiring at the MAF connector, it looks like someone already probed the wires.

Yellow (signal) - 4.4v engine idling at about 800 rpm
Black (ground) - 0.0v
Pink (ref volts) - 14.15v

When I rev the engine, the voltage on the yellow wire drops. I'm at a loss here. The engine definitely has some of the symptoms of a faulty MAF but I'm not sure what the signal voltage should be. Any suggestions?
 
I did all that except I don't have an oscilloscope or access to a Snapon scanner that has the scope and has the grams/sec readout on it. I contacted my mobile mechanic and he has one of those scanners and I'll see if we can't see if the waveform is correct.
 
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