An engine misfire at idle (rough idle), accompanied by illumination or flashing of the Check Engine Light, could indicate a problem with one or more of the intake valves. Revised intake valves & valve locks are available to address this concern.
2003 Jeep Liberty Problem Reports
RepairPal Verified 2003 Jeep Liberty Problem Reports
If the power door locks are buzzing or are intermittently noisy, a new door latch assembly may solve this. The door lock actuators are integrated into the latch assemblies.
Leaks at the front and/or rear differential pinion seal and from the transfer case are common. Low fluid level in the differential or transfer case can result in bearing failure. Damaged bearings commonly cause a whine or growl type noise.
If previous drive belt replacements have not fixed a problem with a chirping belt, there is a service bulletin that outlines a revised drive belt routing.
The sky slider sunroof may not open. A software upgrade for the control module is available which should correct this concern.
The 3.7L V6 and 4.7L V8 in very cold climates (below freezing temperatures) moisture can collect in the Positive Crankcase Ventilation (PCV) system and freeze. This will cause various drivability problems and there are revised PCV system components to repair this concern.
Putting a chamfer on the cam bearing caps, as specified in a service bulletin, can solve a "high pitch snapping noise" heard when the engine is idling or slightly above idle.