BMW Repair: 92 325i, mass airflow meter, coolant temperature sensor

Question
Recently my '92 325i has started bogging down or hesitating when I accelarate. Whereas it used to have plenty of power it now feels under power and my in dash display says I am only getting 16.5 miles to the galllon. When I first bought the car 6 months ago it was getting almost 18 miles to the gallon. I have had regular oil changes and have not been overly hard on the car. Do you know what could be causing the hesitation/lack of power? Thanks in advance for your advice.

Answer
L Ward,
this problem could be caused by a number of things, i would start by looking at the O2 sensor, it could also be the coolant temperature sensor or the mass airflow meter.  it's almost impossible to tell you what without looking at the car.
-cheers