Toyota Repair: check engine & humming / whinig soumd, mass air flow, abu dhabi uae

Question
ted,
i had this "check" alarm on my 1999 toyota avalon dashboard, i brought the car to one shop here in Abu Dhabi, UAE, for diagnosis and they got the following fault:
1. mass air flow circuit malfunction
2. intake air temperature circuit
3. O2 sensor circuit malfunction
4. evaporation ventilation control malfunction

also this humming or whining sound when i'm accelerating @ about 1200 rpm - 1400 rpm the sound is coming but more than this given RPM the sound is gone, i tried to switch off the a/c but the sound is still there, is there some relation with the exhaust pipe, timing belt or the gear bearing, can you please help me with this one, i really hate having this in my car, thanks...

Answer
I need to know what the trouble code was that caused the check engine light, the noise may not be related, it may be coming from the alternator or more likely the power steering pump, check the power steeing fluid level if it is low there may be a leak in the power steering system either at the pump or the seals on the power steering unit.