No. 8 Engine Runs Rough/Rolling Idle: Notes

WARNING: This page is about a different variant/trim than selected.

8	ENGINE RUNS ROUGH/ROLLING IDLE
DESCRIPTION	Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively. Idle speed is too slow and engine shakes excessively.
POSSIBLE CAUSE	Idle learning of drive-by-wire control system is not completed. Poor fuel quality Air cleaner restriction Vacuum leakage Disconnected electrical connectors Air leakage from intake-air system parts No battery power supply to PCM Open or short circuit in PCM ground circuit PCM DTC is stored. Engine overheating MAF sensor or related circuit malfunction A/C system operation is improper. Power steering pressure switch or related circuit malfunction Erratic signal from CKP sensor Ignition system malfunction Ignition coil malfunction Ignition coil related circuit malfunction Spark plug malfunction Fuel leakage from fuel injector Fuel injector clogging Improper operation of drive-by-wire control system Inadequate fuel pressure Fuel pump mechanical malfunction Fuel line restriction or clogging Pressure regulator malfunction (built-in fuel pump unit) Fuel leakage from fuel system Purge solenoid valve malfunction PCV valve malfunction Erratic or no signal from CMP sensor Improper variable valve timing control system operation Low engine compression Improper valve timing WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION .) (See AFTER SERVICE PRECAUTION .) CAUTION: Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

ENGINE RUNS ROUGH/ROLLING IDLE

DESCRIPTION

Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively.
Idle speed is too slow and engine shakes excessively.

POSSIBLE CAUSE

Idle learning of drive-by-wire control system is not completed.
Poor fuel quality
Air cleaner restriction
Vacuum leakage
Disconnected electrical connectors
Air leakage from intake-air system parts
No battery power supply to PCM
Open or short circuit in PCM ground circuit
PCM DTC is stored.
Engine overheating
MAF sensor or related circuit malfunction
A/C system operation is improper.
Power steering pressure switch or related circuit malfunction
Erratic signal from CKP sensor
Ignition system malfunction
- Ignition coil malfunction
- Ignition coil related circuit malfunction
- Spark plug malfunction
Fuel leakage from fuel injector
Fuel injector clogging
Improper operation of drive-by-wire control system
Inadequate fuel pressure
- Fuel pump mechanical malfunction
- Fuel line restriction or clogging
- Pressure regulator malfunction (built-in fuel pump unit)
Fuel leakage from fuel system
Purge solenoid valve malfunction
PCV valve malfunction
Erratic or no signal from CMP sensor
Improper variable valve timing control system operation
Low engine compression
Improper valve timing

WARNING:

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:
- Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
- Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual. (See BEFORE SERVICE PRECAUTION .) (See AFTER SERVICE PRECAUTION .)

CAUTION:

Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.