1: The fio provides 3.3v while the data sheet states a range of 3 - 5.5v. Could it be that 3.3v is sufficient for a few sensors, but not for a larger number?
2: I chose the audio jack cables/connectors due to ease of supply if wanting to expand cable length.Any reason for this cable not being a good solution?
3: Any other idea of what might be wrong?
Can you check with a 5V arduino if it works better ?