DHT22 needs electrical reset?
Your problem is that the DHT22 doesn't like to operate on 3.3V.

That datasheet from Adafruit says on page 5:


  VCC  -  red  wire  Connect  to  3.3  -  5V  power.  Sometime  3.3V  power  isn't  enough  in  which  case  try  5V  power.


The DHT22 uses the AM2302 module. The datasheet for the AM2302 says it is rated for 5V operation, and doesn't mention anything lower.

From the DHT22 datasheet, you can power it using 5V but it will communicate just fine with a 3.3V device like the ESP8266.

It would appear to have an open drain (or open collector) output for data.  It only pulls the data line down.

So, you use a pull up to 3.3V on the data line but power the DHT22 from 5V.