Repair Section
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113
(7) Rough idle
Clogged air cleaner element
Description
Idle speed fluctuates, causing the engine to vibrate.
Possible Cause
• Engine cooling system
• Crankshaft position sensor
• Engine
• Supply pump
• Injector
1 Check parts that may be a source of abnormal
engine vibration.
Repair the engine.
2 Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
sponding circuit.
3 Verify that the engine is not overheated. Repair the engine cooling system.
4 Check the crankshaft position sensor. (Refer to
the crankshaft position sensor check procedure
issued by the vehicle manufacturer.)
Repair or replace the crankshaft position sensor
and/or the corresponding circuit.
5 Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive cir-
cuit diagram issued by the vehicle manufac-
turer.)
Repair or replace the supply pump and drive cir-
cuit.
Troubleshooting complete
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