Not enough info to help. What brand/model CE3, what resistance, what voltage/wattage your driving it with. Always tastes burnt, only sometimes, just started after working well for a while, etc.
In general, burnt taste comes from not enough juice around the coil area of the wick, to high voltage wattage used. Sometimes it can be caused when coils are wrapped way too tight over the wick which prevents getting enough juice around the coil area.