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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 254 (Engine Controls - Trouble Shooting - No Codes - 2.2L) >> Symptoms >> Hesitation, Sag Or Stumble >> Sensor/System

Hesitation, Sag Or Stumble: Sensor/System

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check the Heated Oxygen Sensors (HO2S). The HO2S should respond quickly to different throttle positions. If they do not, check the HO2S for silicon or other contaminates from fuel or the use of improper RTV sealant. The sensors may have a White, powdery coating and result in a high but false signal voltage rich exhaust indication. The PCM will then reduce the amount of fuel delivered to the engine causing a severe driveability problem.
  2. Check for the following that may cause the engine to run rich:
    • Any water intrusion in the HO2S connector.
    • The engine oil contaminated by fuel.
    • An EVAP canister purge condition.
    • Incorrect fuel pressure. Go to FUEL PRESSURE TEST under FUEL SYSTEMS (GASOLINE) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
    • A leaking fuel pressure regulator. Go to FUEL SYSTEM DIAGNOSIS (GASOLINE) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
    • Any leaking fuel injectors. Go to FUEL SYSTEM DIAGNOSIS (GASOLINE) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
    • Any vacuum hoses that are split, kinked, or improperly connected.
    • An air intake duct that is collapsed or restricted.
    • An air filter that is dirty or restricted.
  3. Check for the following conditions that may cause the engine to run lean:
  4. Check for proper operation of the Manifold Absolute Pressure (MAP) sensor. Go to DTC P0105: MANIFOLD ABSOLUTE PRESSURE SENSOR in SELF-DIAGNOSTICS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE - GASOLINE article.
  5. Check for proper operation of the Throttle Position (TP) sensor. Go to DTC P0105: MANIFOLD ABSOLUTE PRESSURE SENSOR in DIAGNOSTIC TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE - GASOLINE article.
  6. Check for proper operation of the Engine Coolant Temperature (ECT) sensor. Go to TEMPERATURE VS. RESISTANCE  table.
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