Inspection Procedure

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the throttle body studs and threaded inserts for looseness or damaged threads.
Inspect the wire harness stud and threaded insert for looseness or damaged threads.

Fig 1: Inspecting Throttle Body Studs
Courtesy of GENERAL MOTORS CORP.
Inspect the fuel rail bolt inserts for looseness or damaged threads.
Inspect the intake manifold vacuum passages for debris or restrictions.

Fig 2: Inspecting Fuel Rail Bolt Inserts
Courtesy of GENERAL MOTORS CORP.
Inspect for damaged or broken vacuum fittings, damaged MAP sensor (1) mounting bore, or broken MAP sensor retaining tabs.
Inspect the composite intake manifold assembly for cracks or other damage.
Inspect the areas between the intake runners.
Inspect all the gasket sealing surfaces for damage.

Fig 3: Inspecting MAP Sensor
Courtesy of GENERAL MOTORS CORP.
Inspect the fuel injector bores for excessive scoring or damage.
Inspect the intake manifold cylinder head deck for warpage.
1. 9.1. Locate a straight edge across the intake manifold cylinder head deck surface.
  Position the straight edge across a minimum of two runner port openings.
2. 9.2. Insert a feeler gage between the intake manifold and the straight edge.
  A intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area is warped and should be replaced.
Fig 4: Inspecting Intake Manifold Cylinder Head Deck For Warpage
Courtesy of GENERAL MOTORS CORP.
Install the MAP sensor (1).
NOTE: Refer to FASTENER NOTICE .
Install the EVAP solenoid, bolt, and isolator.
Tighten

Tighten the EVAP solenoid bolt to 10 N.m (89 lb in).

Fig 5: Installing MAP Sensor
Courtesy of GENERAL MOTORS CORP.