OK, so this problem has been getting worse, and the CEL has been coming on and off.  I ran the diag, and got a 21--Water temperature sensor, and 23--Air Flow Sensor.  I haven't noticed any problems with overheating, etc, so I'm more interested in the air flow sensor.  With the car approaching 200K miles, I'm hesitant to drop $200-300 into it, especially if it's not going to fix the problem.  Just wondering if anyone had similar experiences, and what results they got from changing the sensor. 
  
Thanks!