1997 infiniti j30 p0325, p0400, p0443

my car wouldn't pass emmissions after the codes were cleared. my step father used some tool. he recently replaced the fuel pump. are these codes that i now recieve related. how should i go about repairing this. is it expensive? is it something my step dad could take care of? he is not a mechanic, but he knows a lot about cars.

The check engine light has been on since i returned home after the purchase two years ago. No other problems except that sometimes i can hear the radio and sometimes i can't. A short in the wire maybe. Also the car does not blow cold air though the freon is fine. the mechanic told me i would need to replace the fan.