Four molded gaskets are installed between the cylinder head flanges and the intake manifold.
If these gaskets are not sealed properly, the engine will run rough ("run rough").
If tightening the intake manifold mount does not resolve the problem, replace the gaskets.
Reduce the pressure in the fuel system (see "Reducing the pressure in the fuel system").
Disconnect the negative battery cable.
Remove the air filter (see "Removing and installing the air filter").
After releasing the clamps, disconnect the wiring harness connectors from the injectors and the throttle position sensor...
absolute pressure sensor, intake air temperature sensor, and idle air control valve.
On the side of the engine facing the bulkhead, loosen the nut securing the spacer to the intake manifold, unscrew the bolt securing it to the cylinder block, and remove the spacer.
Remove the engine harness from the holders on the intake pipe at the rear and front.
Using a screwdriver to unfasten the upper engine harness holders at the front and rear...
Remove the harness from the front and rear holders.
Remove the harness from the middle upper bracket on the intake pipe and move it to the side.
Remove the throttle cable end from the intermediate lever ball joint.
Disconnect the purge hose from the intake manifold.
Disconnect the fuel line from the fuel rail (see "Removing and installing the fuel ramps").
Disconnect the hose from the intake manifold to the brake booster by squeezing its fastening clips.
With certain skills, the above operations for disconnecting hoses and wires can be omitted, since to replace the intake manifold gaskets, it is sufficient to move it away from the cylinder head as far as the flexibility of the hoses allows.
Further operations for removing the intake manifold are shown for clarity on the removed cylinder head.
Remove the throttle assembly (see "Removal and Installing the throttle body").
Remove the four upper mounting bolts, unscrew the three lower mounting nuts, and disconnect the intake manifold from the cylinder head.
Remove the gaskets from the intake pipe flange grooves.
Clean the grooves of any old gasket residue.
Replace any gaskets that are severely compressed, hardened, or torn.
Before installing the intake manifold, clean the cylinder head flange of any remaining old gasket.
Place the gaskets in the grooves Intake manifold flanges and install the intake manifold onto the cylinder head. Tighten the intake manifold mounting bolts and nuts evenly in a crisscross pattern, starting with the outer nuts and bolts and moving to the middle ones, to a torque of 25 Nm (2.5 kgf-m).
Install all removed parts and assemblies in the reverse order of removal.