Valve Springs
WARNING: This page is about a different car, the 2003 Suzuki Grand Vitara and 2002 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.
Check valve springs for damage. Use square and flat surface plate to check spring squareness. Using valve spring tester, check valve spring pre-load pressure. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Replace any weak or out-of-square springs.