Disconnect the cable from the negative terminal of the battery and unplug the electrical connector for the oxygen sensor. Remove the spark plug heat shields, if equipped, and the spark plugs. Raise the vehicle and support it securely on jackstands. While working under the vehicle, apply penetrating oil to the exhaust pipe-to-manifold studs and nuts, allowing the fluid to sit for as long as possible to loosen rusty parts. Remove the air cleaner assembly and heat stove tube, if equipped. For the right side manifold, take out the Thermactor hardware, if equipped, and the automatic transmission fluid dipstick tube if necessary, along with the exhaust manifold heat shield, if equipped. For the left side manifold, remove the engine oil dipstick and tube if it obstructs access. Bend back the locking tabs, if equipped, then remove the mounting bolts and separate the manifold from the head, noting the locations of the pilot bolts. Check the manifold for cracks and ensure the bolt threads are clean and undamaged, making sure the mating surfaces are clean before reinstalling. Position the manifold and gasket on the head and install the mounting bolts, tightening them from the center to the ends using a torque wrench in three equal steps until the specified torque is reached. Complete the remaining installation steps in reverse order of removal, then start the engine and check for exhaust leaks.