Disconnect the negative cable from the battery, ensuring you have the correct activation code for the stereo if it has an anti-theft system. Spray penetrating oil on the exhaust manifold fasteners and allow it to soak in. Remove the exhaust crossover pipe from the back of the cylinder heads. Take off the EGR pipe from the exhaust manifold. Unbolt the exhaust manifolds from the cylinder heads and carefully inspect the manifolds and fasteners for cracks and damage. Use a scraper to eliminate all traces of old gasket material and carbon deposits from the mating surfaces of the manifolds and cylinder heads. If there was a gasket leak, have the manifolds checked for warpage at an automotive machine shop and resurfaced if necessary. Position new gaskets over the cylinder head studs, install the manifolds, and thread the mounting nuts into place. Working from the center out, tighten the nuts to the specified torque. Reinstall the remaining parts in the reverse order of removal, using new gaskets when connecting the exhaust pipes. Finally, run the engine and check for exhaust leaks.