A couple of codes to decipher
 

Hello!

My question is to all but i hope the Hyundaitech will weigh in as well
since he has helped me tremendously in the past.

Got 'Check engine light' this morning, hooked up the reader and got a
couple of codes:
0442 and 0100. First is probably related to the filler cap not being
tight so I am not worried much, but the second is "Mass or volume air
flow circuit". Since my wife complains that the car is 'short on
breath' I wonder if this is serious and what should be done. I have a
Sonata 2000 with 106 KMiles on it.

Your response is greatly appreciated.