As the others have said, when it tastes bad change it.
Also agree with learning how to rebuild. I rebuild all my kanger emow Mega's coil's to a vertical coil wicked with japanese cotton. The vape is so much better in my opinion than a shop bought coil and they seem to last longer to me as I have 5 tanks and keep the same tank for each flavour I like so I only change them about once a month.