NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [LF, L3]


12	LACK/LOSS OF POWER - ACCELERATION/CRUISE
DESCRIPTION	Performance is poor under load (e.g., power decrease when climbing hills).
POSSIBLE CAUSE	• Improper A/C system operation • Erratic signal or no signal from CMP sensor • Air leakage from intake-air system parts • Improper VIS operation (if equipped) • Improper VTCS operation • Purge control solenoid malfunction • EGR valve malfunction (Unleaded gasoline model) • Brake dragging • Erratic signal from CKP sensor • Low engine compression • Vacuum leakage • Poor fuel quality • Spark leakage from high-tension leads • Engine overheating • Throttle body malfunction • Spark plug malfunction • Air cleaner restriction • PCV valve malfunction • Improper valve timing due to jumping out of timing belt • Improper variable valve timing control operation (if equipped) • Restriction in exhaust system • Intermittent open or short in fuel pump related circuit • Inadequate fuel pressure • Fuel pump mechanical malfunction • Fuel line restriction or clogging • Fuel leakage from fuel injector • Fuel injector clogging • Intermittent open or short of the MAF sensor, TP sensor and VSS • ATX malfunction (ATX) • Clutch slippage (MTX) Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: • 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 manual. (See BEFORE REPAIR PROCEDURE [LF, L3].) (See AFTER REPAIR PROCEDURE [LF, L3].) Caution • Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.


STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: • Vacuum connection • Air cleaner element • No air leakage from the intake-air system • No restriction of the intake-air system • Proper sealing of the intake manifold and components attached to the intake manifold; such as the EGR valve (unleaded gasoline model), the IAC valve • Fuel quality (e.g. proper octane, contamination, winter/summer blend) Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	Connect the WDS or equivalent to the DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. If an engine stall condition exists, retrieve continuous memory and KOEO DTCs. Are any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test.
2		No	No DTC is displayed: Go to the next step.
3	Is engine overheating?	Yes	Go to symptom troubleshooting "No.17 Cooling system concerns - Overheating".
3	Is engine overheating?	No	Go to the next step.
4	Connect the WDS or equivalent to the DLC-2. Access RPM, MAF, TP and VSS PIDs. Monitor the PIDs while driving the vehicle. Are PIDs within specifications? (See PCM INSPECTION [LF, L3].)	Yes	Go to the next step.
4		No	RPM PID: Inspect the CKP sensor and the related wiring harness for vibration and/or intermittent open/short circuit. MAF PID: Inspect for an intermittent open circuit of the MAF sensor and the related wiring harness. TP PID: Inspect if the TP sensor output increases smoothly. VSS PID: Inspect for an intermittent open circuit of the VSS and the related wiring harness.
5	Visually inspect the CKP sensor and the teeth of the crankshaft pulley. Are the CKP sensor and the teeth of the crankshaft pulley normal?	Yes	Go to the next step.
5		No	Replace the malfunctioning parts.
6	Measure the gap between the CKP sensor and the teeth of crankshaft pulley. Specification 0.5-1.9 mm {0.020-0.075 in} Is the gap within specification?	Yes	Go to the next step.
6		No	Adjust the CKP sensor.
7	Inspect the spark plugs. Is the spark plug wet, covered with carbon or grayish white?	Yes	Spark plug is wet or covered with carbon: Inspect for fuel leakage from the fuel injector. Spark plug is grayish white: Inspect for a clogged fuel injector.
7		No	Install the spark plugs on original cylinders. Go to the next step.
8	Remove and shake PCV valve. Does the PCV valve rattle?	Yes	Go to the next step.
8	Remove and shake PCV valve. Does the PCV valve rattle?	No	Replace the PCV valve.
9	Inspect for restriction in the exhaust system. Is there any restriction?	Yes	Inspect the exhaust system.
9		No	Go to the next step.
10	Install a fuel pressure gauge between the fuel pipe and fuel distributor. Connect a jumper wire between F/P terminal at check connector in main fuse block and ground. Turn the ignition switch to ON position. Is the fuel line pressure correct with the ignition switch to the ON position? (See FUEL LINE PRESSURE INSPECTION [LF, L3])	Yes	Go to the next step.
10		No	Zero or low: Inspect for a clogged fuel line. If normal, replace fuel pump unit. High: Replace fuel pump unit.
11	Inspect the VTCS operation. (See Variable Tumble Control System (VTCS) Operation Inspection.) Does the VTCS function properly?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning parts.
12	Note • The following test should be performed for vehicles with VIS. Go to the next step for vehicles without VIS. Inspect the VIS operation. (See VIS Operation Inspection (L3 Engine Models).) Does VIS function properly?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning parts.
13	Note • The following test is for engines stalling with the A/C on. If other symptoms exist, go to the next step. Connect pressure gauges to the A/C low and high side pressure lines. Turn the A/C on and measure the low side and high side pressures. Are the pressures within the specification? (See REFRIGERANT PRESSURE CHECK.)	Yes	Go to the next step.
13		No	If the A/C is always on, go to symptom troubleshooting "No.24 A/C is always on or A/C compressor runs continuously". For other symptoms, inspect the following: • Refrigerant charging amount • Condenser fan operation
14	Inspect for A/C cut-off operation. (See A/C Cut-off Control System Inspection.) Does the A/C cut-off function properly?	Yes	Go to the next step.
14		No	Inspect the A/C cut-off system components.
15	Disconnect vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side. Plug the open end of the vacuum hose. Drive the vehicle. Does the engine condition improve?	Yes	Inspect if the purge solenoid valve is stuck open mechanically. Inspect the evaporative emission control system.
15		No	Go to the next step.
16	Visually inspect the CMP sensor and projections of the camshaft pulley. Are the CMP sensor and projections of the camshaft pulley normal?	Yes	Go to the next step.
16		No	Replace the malfunctioning parts.
17	Inspect the EGR system. (See EGR Control System Inspection (Unleaded Fuel Models).) Is the EGR system normal?	Yes	Go to the next step. (Unleaded gasoline model) Go to Step 19. (Leaded gasoline model)
17		No	Replace the malfunctioning parts.
18	Note • The following test should be performed for vehicles with the variable valve timing control system. Go to the next step for vehicles without the variable valve timing control system. Inspect the variable valve timing control system operation. (See Variable Valve Timing Control System Operation Inspection (L3 Engine Models).) Does the variable valve timing control system work properly?	Yes	Go to the next step.
18		No	Repair or replace the malfunctioning parts.
19	Is the engine compression correct?	Yes	Inspect the following: • Valve timing • Internal transaxle components (ATX) • Clutch (MTX) • Brake system for dragging
19	Is the engine compression correct?	No	Inspect for the cause.
20	Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, replace the PCM.