97' jeep cherokee laredo shakes when driving

Could be a number of things from ball joints to your pitman arm(arm that steers the tires). It dont sound like tire are way out of balance because yu said it only starts when you hit a bump. If it was me, Id crawl under the front end and start shaking different parts until I figured out what was loose. if its shaking that bad you should definitly be able to tell when you shake it.

Could be a number of things. I've seen tires, steering stablizer, pitman arms, tie rods, etc etc cause this problem. Lock the steering colum, jack up the front end, BOTH SIDES, and try to turn the tires by hand. If you can move it an inch or more, it's your steering components. If not, could be your stablizer or tires. If tires are getting bad, replace those first. (fyi, steering components are easy to do, if you choose to do it yourself. A good parts store will help you with what you need if you can determin where it's loose. Might need a friend to help find the right cause.)