Sometimes the atty will flood from over squonking, but you think it's not getting enough juice. Usually, a dry atty will result in a change in flavor, where as, a overly wet one just gives poor vapor. Try vaping it dry (without inhaling) and squonk while you draw on the atty (without firing) until you *just* feel a slight pressure resistance or hear the tiniest gurgle.
ETA: when I used attys, I always had too much juice if I could see ANY in the catch cup. It should stay completely dry if you're doing it right (takes a few days to really get the hang of it)
ETA2: Don't immediately squonk after you've fired it, let the coil cool down a bit first or you could blow the coil.