whenever it hit some bumps at around 40MPH or so, my car is jumping to the left and the right. what's that a sign of? is it my struts? my car has 63K miles on it. thanks!

 

Tire pressure too high? Check that first since its free.

Could be bad struts but you would really be bottoming out rather than lauunching. I used to experience same thing dropped 3" on GC coilovers since there was no suspenesion travel, the car takes the bump not the suspension.

 

its called a torsion beam, inherent flawof the rear suspension bouncing laterally instead of just vertically, the rear sway bar alleviates this problem from my understanding

 

yeh i think it was the tire pressure....today i checked it..and my two rear tires were around 15psi....i have a slow leak in both of them....pretty $hitty.