Ford Repair: Power Loss for Ford Contour, mass air sensor, mass airflow sensor

Question
I have a 96 Ford Contour 4cyl DOHC. The original miles on the car is 169,000 but the enigne was replaced with another that had 40,000 on it. Recently it lost engine power.  A hand computer stated the code was for a Mass Airflow sensor. I replaced it & the code went away but there is still no power. I changed the fuel filter & the fuel regulator.  I changed the spark plugs.  I have had the engine timing and the catalytic converter checked.  We have checked everything fuel related and still no power.  When it idles it's fine. It's only when you put it in gear that the power loss occurs.  I was also told that it had nothing to do with the transmission. Any help?

Answer
Steve-

  Any time you replace anything like a mass air sensor it's a good idea to reset the computer.  There's an easy way to do this at home without paying a shop $60 to do it for you.  First, disconnect the battery cables (both of them).  Then put your key in the ignition and turn it to the "accessory on" position.  This is the last position before the car cranks (you know...it gives you radio, dash lights, etc.).  Leave it like that for 20 or 30 minutes, then take the key out and reconnect the battery.  This should drain all of the power out of the computer and force it to "relearn" it's new settings automatically.  Sure, you'll have to reset your radio presets, but you just saved $60.  Hope this helps.

Steve