To remove the exhaust manifold, first disconnect the negative battery cable and securely raise the vehicle on jackstands, ensuring to turn off the air suspension switch if applicable. Disconnect the oxygen sensor electrical connector and apply penetrating oil to the exhaust Y-pipe-to-manifold studs and nuts, which may be rusty. Remove the nuts securing the exhaust Y-pipe to the exhaust manifolds, using heat if necessary to loosen them. For the right manifold, disconnect the EGR tube, and for the left manifold, remove the nut holding the oil dipstick tube support and pull the dipstick tube out. Next, remove the mounting bolts to separate the exhaust manifold(s) from the 
Cylinder Head, noting the locations of the bolts and studs while removing old gaskets. Before installation, check the exhaust manifold for cracks and ensure the bolt threads are clean and undamaged, cleaning the mating surfaces thoroughly. If replacing the manifold, remove the oxygen sensor, clean its threads, and apply high-temperature anti-seize compound before transferring it to the new manifold. Position the new manifold and gasket on the cylinder head, installing the mounting bolts and studs, and if warpage is present, install pilot bolts first and elongate holes if necessary. When tightening the bolts, start with the center pair, followed by the front and rear pairs, using a torque wrench to ensure proper tightness in three equal steps. Finally, the remaining steps follow the reverse order of removal, and after installation, start the engine to check for exhaust leaks.