Before servicing the intake manifold, disconnect the negative battery cable, remove the air cleaner housing and take out the mass air flow sensor. Now, remove the fuel rail and all the fuel injectors and remove the vacuum lines to the EGR valve, brake booster, crankcase ventilator and purge valve from the intake manifold. Take off the connectors from the engine harness and the EGR pipe at the EGR valve. Remove both the air pump switchover valves and the bolts that fasten the intake manifold, together with the gaskets. To install, clean up the mating surfaces of the cylinder heads and the intake manifold and fit the new gaskets between them, getting the intake manifold onto the cylinder heads. Make sure to thread in the intake manifold bolts and tighten them at 20 Nm (15 ft. lbs.), before working on the air pump switchover valves which should also be tightened at 20 Nm (15 ft. lbs.). Connect the EGR pipe fitting to the EGR valve, hand-tighten it so it reaches 40 Nm (30 ft. lbs.), put back the mass air flow sensor and then attach the engine harness connectors. With everything connected, put in place the fuel rail, air cleaner housing and fuel injectors. Then attach the negative cable, start up the engine and check for leaks.