CODE P0103 Please Help ME!!!

hello my name is chasy. I have a silver VW Jetta 2001. My check engine light came on. I went to auto zone and got it checked the code was P0304 said it was the mass air flow meter. So I got a new one, on the trip back home it came back home the light came on again with a NEW code (P0103). I don't know what the problem is now. If anyone knows something please let me know.... thanx...

p0304 is cylinder 4 misfire. p0103 i forget though. Check the connector on the maf sensor and see if its plugged in all the way, try wiggling it.