For 1990-2009 cars

### Upper Intake Manifold Cleaning Procedure

1. Remove any remaining gasket and/or gasket material from the following:

• | Throttle body

• | Intake manifold

2. Clean the following intake manifold areas in solvent.

• | Intake manifold gasket sealing areas

• | Intake manifold passages

• | Brake booster hose passage

• | Evaporative emission (EVAP) solenoid passage

• | Positive crankcase ventilation (PCV) vacuum hose passages

Warning: Refer to Safety Glasses Warning in the Preface section.

3. Dry the upper intake manifold and throttle body with compressed air.

### Inspection Procedure

1. Inspect the upper intake manifold for the following conditions:

• | Damage, debris or restrictions to the brake vacuum booster hose port

• | Damage to the throttle body bolt holes

• | Damage, debris or restrictions to the PCV system hose ports

2. Inspect the upper intake manifold for the following conditions:

• | Damage to the intake manifold bolt bosses

• | Damage to the EVAP purge solenoid mounting boss

• | Damage, debris or restrictions to the EVAP purge solenoid port

• | Damage, debris or restrictions in the vacuum passage

• | Gouges or damage to the intake manifold sealing surfaces

• | Damage to the gasket sealing surface for the throttle body

3. Inspect the upper intake manifold sealing surface for warpage.

3.1. | Locate a straight edge across the intake manifold sealing surface.

3.2. | Insert a feeler gage between the upper intake manifold and the straight edge. An intake manifold with warpage in excess of 0.50 mm (0.020 in) must be replaced.

4. Repair or replace the upper intake manifold as necessary.