I have de same problem.I hace a arduino UNO reading two DHT11, one 1m and other 70m distance. There are error only in the fare sensor. The nearly work always correct.¿why? I don´t now. I modificated the library because with the original library, if there is a error reading the sensor, the program go in a while loop and never go down.
I had thought the same:power the senson by a arduino pin and shut down when there is a problem.thants