I need help, i have done a new build. Kiss fc, dys xms30a, emax 2300kv 5045 tri blades, on 4s. I am having what seems to be sync issues, but I dont believe it to be, instead I think it might be the pdb that is not able to handle the amps required. When I give full throttle, my quad stalls for a second, but not every time. Can this be the PDB?

battery: Tattu, 1550mah, 45c, full charge

I don't think it's the PDB. "not handling the amps" results in heat and/or fire. Unless your PDB is really hot after flying, you're not overtaxing it.
I had the same issue before, its the amps, when I switched to 5045 normal prop, issues disappeared, will need get rid of pdb and go straight for wiring. Also need to get some bonka's lipos

Try puting your motor timmings down to low or medium/low. I havent used kiss, there maybe a firmware clash, try calibrating your motors through KISS GUI.