Noises everywhere!

I'm not sure if these noises are common with XJ's, but they sound a little strange:

-When I crank the ignition i hear a thumping sound. I can feel this through the floorboard. I also hear it when I'm sitting at a stoplight on the brakes. If I shift into park and take my foot off the brakes, the sound goes away.

-When I make sharp turns in a parking lot i can sometimes hear a pop sounds

-When I go over large bumps it sounds like the jeep is going to fall apart.

All these sounds have gotten worse since I lifted it about a month ago.

Any ideas?

What year XJ is it? You might just be going over the "large bumps" too fast

Ummm....

It's a Jeep! They make noises! J/K The engine and tranny info would be helpfull too. The more info you give us the more we can help....

The thumping sound when you start and idle sounds like the exhaust hitting the frame crossmember, common when the rubber transmission mount begins to sag. Check the clearance where the pipe goes above the crossmember, and check the engine and transmission mounts for sag and damage.

The popping on corners sounds at first guess like a bad axle shaft universal joint. You can reach into the steering knuckle, where those joints live, and feel for looseness. You can also test for binding by jacking up each front wheel in turn. With the steering at full lock in either direction, try rotating the wheel. If it binds or makes popping and rattling noises, it fails the test.

A whole long list of things from the wheels up to the roof rack can cause noise on big bumps. You'll need to listen harder and be more specific to track them all down, and you'll likely have to get underneath and start wiggling and shaking and yanking on things to start diagnosing. The front control arm design of the XJ makes it pretty harsh on bumps even without a lift, but if you have lifted without changing the geometry of the control arms I would expect it to be worse yet, and even less tolerant of wear or looseness anywhere.

popping sound could also be the track bar. make sure the bolt on the axle end is tight and the ball joint on the other end is lubed.

You might check for a broken motor mount. I know it has nothing to do with your lift, but it is something easy to rule out.