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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 973 (ENGINE CONTROLS - 6.6L (LB7) (INTRODUCTION))REPAIR INSTRUCTIONSFUEL INJECTOR REPLACEMENTFUEL INJECTOR CLEANING AND INSPECTION
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Fuel Injector Cleaning and Inspection

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Fuel Injector Cleaning and Inspection
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: If reusing the old injectors perform the following:
    NOTE: The fuel injector must be cleaned with the proper cleaning equipment. DO NOT use abrasive cleaning methods, such as a metallic brush, to remove deposits. Cleaning an injector with improper tools will damage the fuel injector.
  1. Use a soft bristle non-metallic brush and top engine cleaner, GM P/N 1052626 (Canadian P/N 993026) or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before re-installation.
  2. Inspect the fuel injector nozzle tip (1) for any signs of discoloration (dark yellow, tan, or blue) due to excessive heat.
    3. Fig 1: Fuel Injector Nozzle Tip & Sealing Area
    GM1336202Courtesy of GENERAL MOTORS CORP.
  3. Replace the injector if any damage is found.
  4. Clean the fuel injector high pressure line.
  5. Inspect the fuel injector high pressure line for excessive corrosion or damage to the sealing surfaces (1, 2). Replace the line if any damage is found.
    6. Fig 2: Fuel Injector High Pressure Line Sealing Surfaces
    GM1336212Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.