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Home >> Pontiac >> 2007 >> Grand Prix GXP >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Engine Controls & Fuel - 3.8L - Diagnosis & Troubleshooting) >> Symptoms - Sensors/Systems

Symptoms - Sensors/Systems

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Sensor/System

Symptoms Sensor/System
Find the symptom in the left column and perform the test/inspection procedure in the right column, be sure to review each cell of the table to identify all tests for a symptom.
  • Hard Start
  • Surges/Chuggles
  • Hesitation, Sag, Stumble
  • Cuts Out, Misses
  • Poor Fuel Economy
  • Rough, Unstable, or Incorrect Idle and Stalling
  • Backfire
  • Inspect the mass air flow (MAF) sensor for proper installation, obstruction, contamination, and damage.
  • Inspect the MAF Sensor for proper seating of the connector and terminals.
  • Inspect the manifold absolute pressure (MAP) sensor for proper installation, obstruction, and damage.
  • Ensure the quality of the MAP Sensor vacuum source.
  • Hard Start
  • Detonation/Spark Knock
  • Hesitation, Sag, Stumble
  • Poor Fuel Economy
  • Rough, Unstable, or Incorrect Idle and Stalling
  • Inspect for vacuum leaks and other unmetered air.
  • Test the engine coolant temperature (ECT) sensor for being shifted in value. Refer to the Temperature Versus Resistance .
  • Surges/Chuggles
  • Lack of Power, Sluggishness, or Sponginess
  • Detonation/Spark Knock
  • Poor Fuel Economy
  • Backfire
Monitor the Knock Sensor (KS) System for excessive spark retard activity. Refer to the Knock Sensor description within in the Electronic Ignition (EI) System Description .
Hesitation, Sag, Stumble Inspect the accelerator pedal position (APP) sensor and the related wiring.
Inspect the Throttle Actuator Control (TAC) System for proper operation.
  • Surges/Chuggles
  • Lack of Power, Sluggishness, or Sponginess
  • Hesitation, Sag, Stumble
  • Cuts Out, Misses
  • Poor Fuel Economy
  • Rough, Unstable, or Incorrect Idle and Stalling
  • Backfire
Inspect for contaminated oxygen sensor (O2S).
Poor Fuel Economy Inspect for proper operation of the speedometer.