Mass airflow sensor

I recently installed a new short ram intake and a new mass air flow sensor into my 2001 Ford Focus SE 2.0 L SPI with 51,000 miles. At first, the car seemed to have no power what so ever, but after driving around for an hour or so, it started to run ok, and eventually got back to normal with the added hp, except the check engine light was constantly on. It has been fine for about a month now, until yesterday when I had to disconnect my battery. It reset the mass airflow sensor settings, and my car went back to the point it was when I first installed the short ram and mass airflow sensor where it just has no power to it, I will slam on the gas and it just barley moves. I drove around for over an hour, even got on the highway, and it started to run fine, but I went to drive it today and it was back to just not moving. I have no idea what to do from here, can you help me at all?