Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1999PICKUP C2500, 2D PICKUP, 6.5 F, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 239 (ENGINE CONTROLS - TROUBLE SHOOTING - NO CODES - 3.4L)SYMPTOMSSURGES OR CHUGGLESSENSOR/SYSTEM
1999 Chevrolet Pickup C2500, 2D Pickup, 6.5 F, Standard
Surges Or CHUGGLES: Sensor/System
1999 Chevrolet Pickup C2500, 2D Pickup, 6.5 F, StandardSECTION Sensor/System
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
- Monitor the Heated Oxygen Sensors (HO2S). The HO2Ss should respond quickly to different throttle positions. If not, inspect the HO2S for silicon or other contaminants from fuel or use of improper RTV sealant. Remove the HO2S and visually inspect the portion of the sensor exposed to the exhaust stream to check for contamination. The sensors may have a White powdery coating. Silicone contamination causes a high but false HO2S signal voltage which is a rich exhaust indication. The Powertrain Control Module (PCM) will reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
- Inspect the Mass Airflow (MAF) sensor and related wiring.
- Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
- Monitor the 24X crank sensor and the CMP sensor signal present parameters on the scan tool. If both sensors are not responding, test each sensor feed circuit. Each sensor uses a separate supply circuit but are internally connected to power. Check all CKP sensor A and CMP sensor circuits for intermittents. Go to INTERMITTENTS .
- Monitor the 3X crank sensor parameter on the scan tool. If the 3X crank sensor parameter is not responding, inspect the CKP sensor "B" and related circuits for intermittents. Inspect the Ignition Control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open, or shorted may not set a DTC immediately, but are capable of causing driveability complaints.
- Check the CKP sensor "B" for an internal short. Go to ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.
- Check the Exhaust Gas Recirculation (EGR) system for proper operation.
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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.