Where is the engine plenum gasket in a 1999 Nissan quest 6 Cy?

Answer 1

The upper intake manifold may also be referred to as the intake plentum. If you are going to replace that gasket you might as well change the lower manifold gasket and knock sensor ( under the lower manifold with 1 bolt holding it to block). Do yourself a favor and CHANGE the knock sensor because they fail all the time on that engine. Read the repair manual (could be found at library or bought at parts store) and understand all the steps before attempting.