98 Error codes (5.7 Gas 4wd)

Three error codes were reported and they are as follows:

P0104 - Mass or Volume air flow circuit intermittent

P0102 - Mass or Volume air flow circuit low input

P0340 - Camshaft position sensor circuit malfunction

Not sure if I should replace all the sensors or just start with one at a time. I am looking for some knowledge if possible on these error codes.

Thanks,

Fingers