Maybe the problem is the ballasts,
first,you should check your ballast is AC ballast or DC ballast.because quality of the DC ballast is bad,It's the normal things to make the headlight Flicker
Second,you shoud check the operation declaration of the hid kit,maybe you made a mistake for installing and fitting the wires together
I dont know exactly what's happen to your car,but you could check this things,and normaly,it's would not be happen