Daughter's '92 Lexus ES300 has recently begun idyling rough (coughing between approx..75 and 1.2 - 5 rpm). The fuel exhaust fumes are white, emitting a lingering - but not thick - cloud from the pipe with a rich smell of gasoline.
I do not see leaking fuel lines or disconnected vacuum hoses under the hood.
Any ideas where to look for problem?
Probable causes of an engine running rich are as follows: 1. Excessive fuel pressure can be cause by restricted fuel return line
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.