Help w/Check Engine Light - Engine Codes

Hi,
 
I am new to the forum and hoping someone can help...
 
We recently bought a 1996 Cabrio w/2.0L engine (165K) and the check engine light is on.
 
I went to AutoZone to have the codes read and are as follows:
 
P0422: Catalyst efficiency low-bank 1 - The PCM has determined that the main catalyst efficiency for bank 1 is below threshold for the current engine operating conditions.
P0102: MAP/BARO or MAF sensor condition - The PCM has determined that the mass air flow input is lower than expected for the current engine operating conditions.
P0172: Fuel trim bank one condition - The PCM has determined that during testing, the fuel system for bank 1 was too rich.
 
Does anyone know what might be throwing these codes?  Are they common?
 
I reset the computer, but the light came back on.  Any help is greatly appreciated.  Thanks!