To remove the rocker arm assemblies from a 2.0L engine, position the number one piston at Top Dead Center, disconnect the negative battery cable from the ground stud on the left shock tower, and remove the valve cover. Before removing the rocker arm shafts, mark the front shaft as the intake rocker arm shaft and the rear shaft as the exhaust. Loosen the rocker arm shaft bolts gradually until the valve spring pressure is relieved, then completely loosen the bolts without removing them to keep the assembly intact. Lift the rocker arms and shaft assemblies from the cylinder head, securing any dislodged hydraulic valve lash adjusters with electrical tape if necessary. Disassemble the rocker arm shaft components, marking all parts for reassembly in their original locations. For a 2.4L engine, remove both camshafts, then lift off the rocker arms and hydraulic valve lash adjusters, ensuring each is returned to its original location. Inspect the rocker arms and lash adjusters for wear or damage, replacing any that show signs of excessive wear. Before installation, ensure the lash adjusters are partially filled with engine oil, and if necessary, pump the plunger to eliminate excessive travel. Reinstall the rocker arms in their original locations, ensuring plastic spacers are correctly positioned, and install the rocker arm assemblies with the notches facing up. Tighten the rocker arm bolts in sequence to the specified torque, then follow the reverse steps for installation. After starting the engine, expect initial "tapping" noises from the adjusters; if they do not become silent after a warm-up and speed increase, replace the defective assembly. For the 2.4L engine, follow similar procedures for installation and testing of the lash adjusters and rocker arms.