You must both reduce fuel system pressure and detach the car's negative battery cable before you can take off the upper intake plenum on these cars. Empty the coolant into a clean jug before taking off the V-bank cover, which comes loose when you unscrew and lift out the two Allen bolts. Unplug everything from the throttle body - the electrical cords, air valves, and coolant bypasses - and move the throttle lever aside; you can leave the throttle body in place unless you need to clean or replace its gaskets. Unplug the EGR pipe where it meets the intake plenum and remove the two bolts from the intake braces at the firewall side of the rear cylinder head. Then, take out the plenum mounting hardware and lift it from the lower intake manifold. Before taking the lower intake manifold off, you need to pull out the electrical cords from all the fuel injectors and remember their connection order. Take off the air assist and heater hoses from the left end of the intake manifold, detach the fuel line from the fuel rail. Carefully unscrew and remove the eight mounting nuts or bolts holding the intake manifold to the engineblock, but be cautious to keep the two gasket surfaces from separating. We must replace the water transfer hose every time we take off the intake manifold while doing other engine work. When putting the intake manifold back on, remove all previous gasket debris and sealants from both the manifold and cylinder heads. Clean the connection parts, put on fresh gaskets, and put the manifold onto the engine, making sure the gaskets stay in place before threading on the nuts/bolts. Put the nuts/bolts on in three small steps of equal tension, then finish installing everything backward from how you took it apart. Put a new gasket in place for where the intake meets the plenum. In the end, add more coolant, start the engine, and search for fuel, vacuum, and coolant leaks.