Issues with Dust Sensor

I am getting very inconsistent results with the dust sensor.  It will alternately detect particles for several cycles, then detect nothing for quite a few cycles with an occasional concentration error mixed in.  I've checked the wiring multiple times and swapped the powersave with the one for the temp probe, but I still get the same results.  I swear I'm not carrying it into a clean room and back out. (Not that a clean room will produce readings of zero either!)  What is causing this?

Here is the output from the most recent test run:

$ sudo python testDust.py
Air Quality Measurements for PM2.5:
6819 particles/0.01ft^3
10 ugm^3
Current AQI (not 24 hour avg): 44

Air Quality Measurements for PM2.5:
486508 particles/0.01ft^3
758 ugm^3
Current AQI (not 24 hour avg): 500

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Concentration Error

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Concentration Error

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
15844 particles/0.01ft^3
24 ugm^3
Current AQI (not 24 hour avg): 77

Air Quality Measurements for PM2.5:
488 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 3

Air Quality Measurements for PM2.5:
1782 particles/0.01ft^3
2 ugm^3
Current AQI (not 24 hour avg): 11

Air Quality Measurements for PM2.5:
8364 particles/0.01ft^3
13 ugm^3
Current AQI (not 24 hour avg): 52

Concentration Error

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
20245 particles/0.01ft^3
31 ugm^3
Current AQI (not 24 hour avg): 91

Air Quality Measurements for PM2.5:
703 particles/0.01ft^3
1 ugm^3
Current AQI (not 24 hour avg): 4

Air Quality Measurements for PM2.5:
99402 particles/0.01ft^3
155 ugm^3
Current AQI (not 24 hour avg): 205

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Concentration Error

Air Quality Measurements for PM2.5:
0 particles/0.01ft^3
0 ugm^3
Current AQI (not 24 hour avg): 0

Air Quality Measurements for PM2.5:
3479 particles/0.01ft^3
5 ugm^3
Current AQI (not 24 hour avg): 22

^CTraceback (most recent call last):
File "testDust.py", line 27, in <module>
time.sleep(30)
KeyboardInterrupt