NO.8 ENGINE RUNS ROUGH/ROLLING IDLE [MZI-3.5]
DESCRIPTION AND POSSIBLE CAUSES
2
Remove thermostat and inspect operation.
(see
THERMOSTAT
REMOVAL/INSTALLATION [MZI-
3.5]
.)
(see
THERMOSTAT INSPECTION
[MZI-3.5]
.)
Is thermostat normal?
Yes
ECT and thermostat are normal.
Go to the next step.
No
Access ECT PID on the M-MDS.
Inspect for both ECT PID and
temperature gauge on instrument
cluster readings.
If temperature gauge on instrument
cluster indicates normal range but
ECT PID is not same as temperature
gauge reading, inspect CHT sensor.
If temperature gauge on instrument
cluster indicates cold range but ECT
PID is normal, inspect temperature
gauge and heat gauge unit.
3
Is throttle body free of contamination?
Yes
Inspect for air leakage from the
intake-air system components while
racing the engine to higher speed.
No
Clean or replace throttle body.
4
z
Verify test results.
{
If normal, return to diagnostic index to service any additional symptoms.
(See
ENGINE SYMPTOM TROUBLESHOOTING [MZI-3.5]
.)
{
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
z
If vehicle is repaired, troubleshooting completed.
z
If vehicle is not repaired or additional diagnostic information is not
available, replace the PCM.
(See
PCM REMOVAL/INSTALLATION [MZI-3.5]
.)
8
ENGINE RUNS ROUGH/ROLLING IDLE
DESCRIPTION
z
Engine speed fluctuates between specified idle speed and lower speed and
engine shakes excessively.
z
Idle speed is too slow and engine shakes excessively.
z
Air leakage from intake-air system parts
z
A/C system operation is improper
z
Erratic signal to ignition coil
z
Spark plug malfunction
2007 Mazda CX-9 Grand Touring
2007 ENGINE PERFORMANCE Symptom Troubleshooting (MZI-3.5) - CX-9
Microsoft
Sunday, November 15, 2009 9:27:37 AM
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