I have a 1998 acura Integra gsr just bought this car 1 month ago...when i am driving i feel my engine moving and when i down shift it have a sound like it hitting something.... i ask my dad what it is and he said it does not have a crossmember and i try looking on ebay and it not what i am looking for please help!!!!!!!

 

engine mounts check them out it's not a surprise if they've gone bad they're meant to reduce NVH not last for a long time. checking the subframe bolts is worth a go but don't expect them to be loose I've never really heard of that happening another possibility is a a bad axel as they can make a clunking noise that would sound like something hitting.

 

Probably a torn rear engine mount and/or torn torque mounts.

The car isn't supposed to have a cross member under the engine.