3000GT VR-4 AWD V6-2972cc 3.0L DOHC MFI Twin Turbo (1998)
(2) Deposit on the throttle valve
(3) Air leaking into the intake manifold through gasket gap
(4) Loose EGR valve seat
(5) Poor combustion in the cylinder (faulty ignition plug, ignition coil, injector,. low compression pressure, etc.)
INSPECTION
Using Scan Tool
NOTE: When the vehicle is new [within initial operation of about 500 km (300 miles)], the stepper motor steps may be about 30 steps more than
standard.
CAUTION: When the selector lever is shifted to the "D" range, the brakes must be used to prevent the vehicle from moving forward.
Using Oscilloscope
(1) Connect the probe to each oscilloscope pick-up point as shown in the circuit diagram.
(2) Start the engine.
(3) When the air conditioning switch is turned on, the idling speed increases to operate the idle speed control. Check the instantaneous waveform.
NOTE: Keep in mind that the waveform can be observed only when idle speed control is in operation.
HARNESS INSPECTION
Measure the power supply voltage of idle air control motor.
-
Idle air control motor connector: Disconnected
-
Ignition switch: ON
Voltage (V): Battery positive voltage
OK: GO TO STEP 2
NG: Repair the harness. (MFI relay - A2) (MFI relay - A5)
