take a good, close look at your coil. If any part of it is loose and not touching the wick, it will give a burnt, metallic taste. I can always tell when my coil and wick have shifted, I feel the need to tilt. Tension is the name of the game. Too much and you get hot spots and a burnt taste, too little and you get a burnt taste. I wrap my wick out of the device to get a nice, even tension all around the coil.