2000 Chevy Prizm Car has no power Help!

Hello, I noticed some hesitation and loss of power in my Prizm, and replaced the fuel pump, and got a tune up. This helped mildly. I then read about cleaning the mass airflow sensor. I took out the old one, and used an electrical cleaner and cleaned it. I put it back in, and boom, instant results. I got my power back, but then I must not have snapped it into place because it got unplugged. I noticed more hesitation, and went to check on it, and I saw that it was unplugged. Well I just plugged it back in, and then there was absolutely no power, it would just coast, no acceleration. I talked to someone, and they told me to reset it by unplugging the battery, then re install the MAFsensor. I unplugged the battery, then insalled the circuit, then plugged the battery back in. Now it has some accerlation, but only up to 30 mph. Is there something else I need to do? Help!