I am far from a pro, painted 6 vehicles so far as a hobby. My latest gun is a Devilbiss FLG4. I clean mine with cheap lacquer thinner.
4 inches is way too close, should be getting good coverage much farther away.
I've never used that same paint but every paint I've used required thinning.
Is the vent hole in the cup clear?
Make sure the gun is clean, soak the nozzle in lacquer thinner, pull out the needle and make sure there is no paint buildup on it.
Sounds to me like the paint is too thick or the air pressure is too low.
