Hi, I have a 94 Ford Ranger Extended Cab, V-6, manual transmission. I have a check engine light on with a code for Mass Air Flow Sensor below minimum voltage. I have replaced the MAF sensor with three different ones and have the same problem and code. Problem - After driving for 3-5 miles the check engine light comes on and will stay on until the truck is turned off and back on. When restarted the light will be off, but will come on much quicker than the first drive of the day. When the light comes on, I will lose power when going up a hill, but the truck keeps running at highway speeds. When I reduce speed and stop at a light, or stop sign, the truck will often die. When I restart, or if it doesn’t die, I will get intermittent gas pedal response. The truck will try to die while I push the gas pedal to the floor and may or may not respond after a couple of seconds. It will then jump forward in response and lose response again after a couple of seconds. At times when I restart the truck, it will immediately die after starting. Another odd thing is that when it is wet outside I will only get about a half a mile before it throws a fit. The mechanic is adamant that it is the MAF sensor and I have just had bad luck with three defective sensors from Advance Auto Parts. I believe this mechanic is more defective than the MAF sensor. 
Any help you can provide would be greatly appreciated.
BTW - I have replaced all plugs, wires, and fuel filter. Also, it doesn’t seem to matter if I am running the A/C or heat.
Thank you very much! If you help identify this problem, I will work out a “Thank you” gift in return.
What is the exact number code that is stored in the computer. These codes do not and cannot indicate that a part is bad. They indicate out of spec issue in systems.
The wiring to the MAF sensor should be tested. You should also check for any air leaks between the MAF sensor and the intake. The codes just tell you where to start looking for the problem. They never absolutely say that a particular part is bad.
I can’t remember the exact code number tonight, will check numbers given tomorrow. I do know that the code (according to my Haynes manual) says “Mass Air Flow Sensor Below Minimum Voltage”.
I suspected a wiring issue, but the same mechanic was also persistent that wiring couldn’t be the issue. Needless to say, I won’t be going back to him.
Is it possible to test the wiring, or do I need to have a reputable mechanic begin tracing wires? I hesitate to do that because I know that at $70+ per hour can add up quick chasing wires and this is a 94 Ford Ranger.
Thanks for your quick responses already and in the future. I am truly grateful for your helpfulness. I have very little knowledge of vehicles, so your advice is invaluable. Also, if you know of a good mechanic in the Washington D.C. area, please let me know.
Could this be a ripped zip tube? I’ve seen a 3.0L ranger with a broken motor mount rip the air inlet “zip” tube. The air would bypass the MAF and, of course, the check engine light came on with a MAF sensor code.