EM--6
--
ENGINE MECHANICAL
CO/HC (2RZ--FE)
CO
HC
Problems
Causes
Normal
High
Rough idle
1. Fault ignitions:
S
Incorrect timing
S
Fouled, shorted or improperly gapped plugs
S
Open or crossed high--tension cords
2. Incorrect valve clearance
3. Leaky intake and exhaust valves
4. Leaky EGR valve
5. Leaky cylinders
Low
High
Rough idle
(Fluctuating HC reading)
1. Vacuum Leaks:
S
PCV hose
S
Intake manifold
S
Throttle body
S
Vacuum hose
S
Intake chamber
High
High
Rough idle
(Black smoke from exhaust)
1. Restricted air filter
2. Plugged PCV valve
3. Faulty EFI system:
S
Faulty fuel pressure regulator
S
Clogged fuel return line
S
Defective water temperature sensor
S
Defective intake air temperature sensor
S
Faulty engine ECU
S
Faulty injectors
S
Faulty Air flow meter
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Pages From Supplement
3RZ-F,3RZ-FE