lean error obd code 99 trans am

My daughter just phoned me and has an intermittent check engine light. The error codes are P0171 and P0174. These are lean error codes for left and right bank respectively. I don't have the car here yet, but here are my questions.

1) How many O2 sensors are there? does this sound like they are bad?

2) Is it the MAF or MAP?

3) Anything else to check?

It is intermittent and I don't know the circumstances setting the error or clearing it when it goes away. It is a 99 Trans Am, V8. Car runs fine even when the check engine light is on.

Thanks in advance.

1. There are 2 O2's on each side. One before the cat and one after per bank.
2. Could be. Most likely the MAF. May need cleaned.
3. Fuel pump.

Also check for a vaccum leaks....and yes..trying cleaning the MAF....it works on Fords!!!!