Rough Idle/Engine Stalls at Idle — After Warm-up
F2-37flowchart10 ROUGH IDLE/ENGINE STALLS AT IDLE — AFTER WARM-UP
Engine runs normally at idle during warm-up but stalls or vibrates excessively after warm-up.
NOTE
[TROUBLESHOOTING HINTS] (1) Idle-speed control system malfunction. (2) Air/fuel mixture too lean: Air leakage; Low fuel line pressure. (3) Air/fuel mixture too rich: Fuel injection control malfunction (Correction for coolant temperature). (4) Poor ignition. (5) Low engine compression.
Rough Idle/Engine Stalls at Idle — After Warm-up
1
STEP 1: Is "00" displayed on SST with ignition switch ON? (Self-Diagnosis Checker, System Selector 49 B019 9A0, SELECT SW: A, 49 H018 9A1, Monitor Light) (page F2-73)
No
Diagnostic trouble code No. displayed: Check for cause (Refer to specified check sequence) (page F2-74)
Yes ("00" displayed): Go to next step
2
STEP 2: Are ECM terminal voltages OK? 1C-Starter signal; 2E-Engine coolant temperature sensor; 3D-Sensor ground (page F2-141)
No
Check for cause (page F2-141)
Yes: Go to next step
3
STEP 3: Disconnect high-tension lead at idle; does engine speed decrease equally at all cylinders?
No: Go to step 9
return to step 6
Yes: Go to next step
4
STEP 4: Is intake manifold vacuum at idle correct? Vacuum: More than 450 mmHg {17.7 inHg}
No
Check for air leakage of intake-air system components (page F2-95)
Yes: Go to next step
5
STEP 5: Is air cleaner element clean? (page F2-70)
No
Replace air cleaner element
Yes: Go to next step
6
STEP 6: Disconnect idle air control valve connector at idle; does engine speed increase?
No
7
Replace idle air control valve (page F2-95)