Also what module are you using - do you have a picture?
The bare Bluetooth modules should definitely be run from 3.3v (not 5v) - but it sounds like you have a breakout board and that may have a voltage regulator on it.
It's actually possible that the power supply to the board is too noisy (maybe even because of the wires you're using) - you may find that putting a capacitor (around 10uF) across the power lines on the Bluetooth board will sort out any problems you might be having.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Are you using an Arduino, or an Espruino board?
Also what module are you using - do you have a picture?
The bare Bluetooth modules should definitely be run from 3.3v (not 5v) - but it sounds like you have a breakout board and that may have a voltage regulator on it.
It's actually possible that the power supply to the board is too noisy (maybe even because of the wires you're using) - you may find that putting a capacitor (around 10uF) across the power lines on the Bluetooth board will sort out any problems you might be having.