Car bounces/shakes when drifting

[punxva]

Hey lately I’ve noticed that my car sometimes like starts bouncing like hell when I’m drifting, like I don’t use the e-brake, I power over, and it just starts shaking, until either I shift, or I let off the gas, wtf is making this problem, I’ve got a stock 240 (suspension wise) and got pretty new Falken Azenis on all 4. I thought at first it may be my shocks or some other suspension part, but I wanted some more opinions before I went off and spent lots of $ on every part, when I could just isolate the problem with a few.