No.12 Lack/Loss Of Power-Acceleration/Cruise: Notes

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

NO.12 DESCRIPTION AND POSSIBLE CAUSE

12	LACK/LOSS OF POWER - ACCELERATION/CRUISE
DESCRIPTION	The performance is poor under a load (e.g., power loss when climbing hills).
POSSIBLE CAUSE	Vacuum leakage Air leakage from intake-air system Air cleaner restriction Air suction at intake-air system (between MAF sensor and intake ports) Throttle body malfunction Improper SSV operation Improper APV operation* Improper VDI operation Improper operation of drive-by-wire control system (abnormal accelerator position and TP signals to PCM) Drive-by-wire control system operates in fail-safe mode (abnormal accelerator position and TP signal to PCM) Poor fuel quality Inadequate fuel pressure Pressure regulator (integrated in fuel pump unit) Fuel pump mechanical malfunction Fuel line restriction or clogging Fuel injector improper operation Fuel injector malfunction (leakage, clogging, improper injection amount) Intermittent open or short in fuel pump related circuit Restriction in exhaust system Leakage or damaged exhaust manifold Purge solenoid valve malfunction (stuck open) Erratic signal from eccentric shaft position sensor Improper ignition timing control (abnormal ECT, IAT, MAF and knock sensor signals to PCM) Improper fuel injection control (abnormal MAF, ECT, front/rear HO2S and knock sensor signals to PCM) MAF sensor improper installation Spark leakage from high-tension leads Spark plug malfunction Incorrect spark plug heat range Engine overheating Low engine compression Engine internal malfunction Abnormal engine oil condition (viscosity, deterioration) Low oil pressure Excessive fuel pressure Air mixed in oil line Metering oil pump malfunction Leakage or clogging in oil pipe Leakage or clogging in oil nozzle Metering oil pump malfunction Improper metering oil pump control operation Improper A/C system operation Brake dragging Low tire pressure AT malfunction (AT) Improper operation of torque converter clutch control (AT) Clutch malfunction (MT) WARNING: The following troubleshooting flow chart contains 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 REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this article. (See BEFORE REPAIR PROCEDURE .) (See AFTER REPAIR PROCEDURE .) CAUTION: Disconnecting/connecting quick release connector without cleaning it may possibly 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.

LACK/LOSS OF POWER - ACCELERATION/CRUISE

DESCRIPTION

The performance is poor under a load (e.g., power loss when climbing hills).

POSSIBLE CAUSE

Vacuum leakage
Air leakage from intake-air system
Air cleaner restriction
Air suction at intake-air system (between MAF sensor and intake ports)
Throttle body malfunction
Improper SSV operation
Improper APV operation*
Improper VDI operation
Improper operation of drive-by-wire control system (abnormal accelerator position and TP signals to PCM)
Drive-by-wire control system operates in fail-safe mode (abnormal accelerator position and TP signal to PCM)
Poor fuel quality
Inadequate fuel pressure
Pressure regulator (integrated in fuel pump unit)
Fuel pump mechanical malfunction
Fuel line restriction or clogging
Fuel injector improper operation
Fuel injector malfunction (leakage, clogging, improper injection amount)
Intermittent open or short in fuel pump related circuit
Restriction in exhaust system
Leakage or damaged exhaust manifold
Purge solenoid valve malfunction (stuck open)
Erratic signal from eccentric shaft position sensor
Improper ignition timing control (abnormal ECT, IAT, MAF and knock sensor signals to PCM)
Improper fuel injection control (abnormal MAF, ECT, front/rear HO2S and knock sensor signals to PCM)
MAF sensor improper installation
Spark leakage from high-tension leads
Spark plug malfunction
Incorrect spark plug heat range
Engine overheating
Low engine compression
- Engine internal malfunction
- Abnormal engine oil condition (viscosity, deterioration)
- Low oil pressure
- Excessive fuel pressure
- Air mixed in oil line
- Metering oil pump malfunction
  - Leakage or clogging in oil pipe
  - Leakage or clogging in oil nozzle
Metering oil pump malfunction
Improper metering oil pump control operation
Improper A/C system operation
Brake dragging
Low tire pressure
AT malfunction (AT)
Improper operation of torque converter clutch control (AT)
Clutch malfunction (MT)
WARNING:
The following troubleshooting flow chart contains 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 REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this article.
  (See BEFORE REPAIR PROCEDURE .)
  
  (See AFTER REPAIR PROCEDURE .)
CAUTION:
- Disconnecting/connecting quick release connector without cleaning it may possibly 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.