2004 Jeep Cherokee Timing belt

So you have an engine running problem, you didn't bother to list the engine size, gas or diesel, or any other details. If this problem just started once the timing belt was replaced, it should be pretty obvious the timing needs to be rechecked. If the engine uses a tensioning device, activating that can pull all the slack to one area and cause the camshaft(s) to turn a tooth or two. That's plenty to cause running problems.