Cracking noise is fine actually, that means your juice flow is as it should be. However in some cases it can crackle a lot if a) you vaping extreme sweet juices, the sugar or as we call it gunk sits right on top of the wire, cleaning it can help. B) you're using something like a staggered fused Clapton, the very noticeable little pockets on the wire, will collect all the juice and will crackle next time you're firing it, solution would be multiple, one let the fire button go before you end your inhale, inhaling the last vape while the coil is cooling down, that will remove that issue. Another solution purge your tank before inhaling, same result tho just different method, or/and lower the wattage. Spit back is absolutely different. So either lower the wattage and see if that changes, rewick, use different coils or/and different juice, there's not much else to it.
