Upgraded Emissions

DEFINITION
A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

PRELIMINARY CHECKS
Perform the "Visual and Physical Checks" as described in Preliminary Checks. Testing and Inspection

Make sure the customer has an actual problem.

Remove Air Cleaner (ACL) and check for dirt, or for being plugged. Replace as necessary.

CHECK: PCV valve system for proper operation by placing finger over inlet hole in PCV valve end several times with the engine idling. PCV valve should snap back. If not, check PCV valve hose for blockage or deterioration and replace if necessary. If PCV valve still fails this test, replace it with the correct part number PCV valve.

COOLING SYSTEM
CHECK: For obvious overheating problems.
CHECK: For proper operation of the electric radiator fan.
CHECK: Low engine coolant.
CHECK: Loose water pump belt.
CHECK: Restricted air flow to radiator, or restricted water flow through radiator.
CHECK: Faulty or incorrect thermostat.
CHECK: Correct coolant solution.

SENSOR
CHECK: Engine Coolant Temperature (ECT) sensor for a shifted value. Compare ECT sensor resistance value to those in Engine Coolant Temperature Sensor / Specifications.

FUEL SYSTEM

NOTICE: To determine if the condition is caused by a rich or lean system, the vehicle should be driven at the speed of the complaint. Monitoring Heated Oxygen Sensor (HO2S) voltage with Tech 1 scan tool will help identify the malfunction.
Lean - HO2S voltage below 450 mV.
Rich - HO2S voltage above 450 mV.

CHECK: Fuel pressure, refer to Chart A2-7B Fuel System Pressure Check for fuel pressure check procedure. Chart A2-7B Fuel System Pressure Check

For additional checks, refer to On-Board Diagnostic System Check. Testing and Inspection

CHECK: For poor fuel quality, proper octane rating.

NOTICE: If HO2S voltage readings are normal and there are no engine mechanical faults, fill fuel tank with a premium gasoline that has a minimum octane rating of 92 and re-evaluate vehicle performance.

IGNITION SYSTEM
CHECK: Ignition timing.
CHECK: Spark plugs for proper heat range.
CHECK: Ignition wires for shorts or faulty insulation.
CHECK: For misfiring, crossfiring or cutting out under load.

ENGINE MECHANICAL
CHECK: For carbon buildup. Remove carbon with top engine cleaner. Follow instructions on can.
CHECK: For incorrect basic engine parts such as cam, heads, pistons, etc.
CHECK: For excessive oil entering combustion chamber.

ADDITIONAL CHECKS
CHECK: Exhaust Gas Recirculation (EGR) system operation.
CHECK: For proper transaxle shift points.
CHECK: For correct Engine Control Module (ECM), see Technical Service Bulletins.