What's wrong with them? Are they stuck? (You can try the old trick where you slowly pour Transmission Fluid into the carburetor while the engine is running, taking care not to stall it. Don't do it near your neighbors, because it creates a hell of a lot of smoke). Are the valves burned? If so, then you'll have to pull the head.
The 2014 Jeep Cherokee has 16 valves.
The 2006 Jeep Grand-Cherokee has 12 valves.
The 2008 Jeep Grand-Cherokee has 12 valves.
The 2001 Jeep Grand-Cherokee has 12 valves.
The 2003 Jeep Grand-Cherokee has 12 valves.
The 2002 Jeep Grand-Cherokee has 12 valves.
The 2014 Jeep Grand-Cherokee has 24 valves.
The 2010 Jeep Grand-Cherokee has 12 valves.
The 2013 Jeep Grand-Cherokee has 24 valves.
The 2005 Jeep Grand-Cherokee has 12 valves.
The 2004 Jeep Grand-Cherokee has 12 valves.
The 2007 Jeep Grand-Cherokee has 12 valves.