Response is delayed for a moment when the accelerator pedal is depressed. This occurs at every vehicle speed. Usually, this situation is most notable when starting the vehicle from the stopped state. Engine stalling may occur in severe situations.
Perform the Diagnostic system check - engine controls.
Perform the Fuel supply pump functional inspection.
Compare the vehicle with a similar vehicle. Check if any problem exists in the vehicle.
Remove the air cleaner and inspect for contamination, collapsing in the air duct, or any condition that restricts the flow.
Inspect whether the transmission shift pattern and the down shift operation are normal.
Inspect the fuel quality.
Inspect the engine oil level and oil quality.
Ensure that the ground of the ECM is free of dirt and is fixed securely in the correct position.
Verify the Injector ID Code of each cylinder.
Check the scan tool data list.
Check for related Service Bulletins.
Compare the Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), and Fuel Temperature parameters while the engine is cold. If the difference between the temperature values is 5°C {9°F} or more when the engine is cold, inspect for high resistance in each circuit and for sensor failure.
{When the ignition switch is turned ON, the MAF sensor is heated, and as a result, the IAT shows a higher value than the normal intake air temperature.}
Observe the Mass Air Flow (MAF) parameter on the scan tool, and check for MAF sensor malfunctions or slow reaction.
Observe the Fuel Rail Pressure (FRP) Sensor parameter on the scan tool. It is normal if the Fuel Rail Pressure (FRP) Sensor parameter shows 0.9 to 1.0 V when the ignition switch is turned ON without starting the engine after 30 seconds or more have passed since the stop of engine operation. If not, inspect for high resistance in each circuit and for any sensor failure.
With the vehicle in neutral and idling, completely depress the accelerator pedal while observing the Fuel Rail Pressure (FRP) parameter and Desired Fuel Rail Pressure (FRP) parameter. The difference displayed should always be held to 5 MPa {725 psi} or less.
Observe the Accelerator Pedal Position (APP) parameter. It is normal if the Accelerator Pedal Position (APP) parameter changes linearly from 0 to 100% according to the accelerator pedal operation.
Observe the Boost Pressure parameter and Barometric Pressure (BARO) parameter when the ignition switch is ON and the engine is OFF. It is normal if the difference between both parameters is 7.0 kPa {1.0 psi} or less.
The CKP sensor is securely installed, and the flywheel is not damaged.
Inspect for air in the fuel system.
Inspect for water in the fuel.
Inspect whether the fuel is frozen.
Inspect whether the fuel filter warning light illuminates intermittently or frequently.
Inspect the fuel filter for clogging.
Inspect for external fuel leakage and excessive engine oil.
Inspect for fuel leakage from the pressure limiter and injector.
Inspect for collapsing, twisting, improper tightening, cracking, or clogging in the fuel system between the fuel tank and the fuel supply pump.
Inspect the vent valve and hose of the fuel tank for clogging.
{The piping may be clogged due to foreign material from the fuel tank entering the fuel system.}
Inspect the operation of the fuel supply pump.
{The fuel supply pump must be timed with the engine, and the adjusted value should be learned by the ECM.}
Perform the Cylinder Balance with a scan tool.
Perform the Injector Forced Drive with a scan tool.
Observe the Fuel Compensation parameter for each cylinder on the scan tool while idling.
Inspect the air cleaner, air intake duct, and intercooler for clogging, holes, or leakage.
Inspect for any condition that restricts flow within the turbocharger intake duct.
Inspect for a stuck intake throttle valve.
Inspect the inlet cover for clogging or air leakage.
Inspect the MAF sensor for dirt or damage.
Inspect the turbocharger turbine wheel, shaft, or compressor wheel for wear or damage.
Inspect the operation of the turbocharger control actuator.
Inspect whether the exhaust system flow is restricted.
Inspect the compression pressure of the engine.
Inspect the valve clearance.
Inspect the valve spring for breakage and fatigue.
Inspect the camshaft for wear.
Inspect whether the EGR system is operating properly. (Euro2 and Euro4)
Perform the EGR control system check. (Euro2 and Euro4)
Inspect the relief valve and relief valve control solenoid valve for sticking. (Except Euro2 and Euro4)
Inspect whether the engine has overheated.
Inspect the operation of the A/C.
Inspect the operation of the torque converter clutch. (Automatic transmission models)