what causes erratic idle on bmw 318 n42 engine when engine is warm .

2002 BMW 318I
108,000 MILES
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TERENCE MC LEAN
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  • 1 POST
the vehicle works fine for the first twenty or so minutes then begin to give an erratic idle thereafter. This increases when ac, and head lights are turned on.
Mar 15, 2012 at 8:21 PM
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RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Have the alternator and fuel pressure checked-also refer to this links:https://www.2carpros.com/articles/engine-misfires-or-runs-rough

1.Defective spark plugs

2.Inadequate spark/coil,defective spark plug wire.

3.Lack of compression

4.False air leakage.

5.Faulty fuel injectors.

6.Insufficient fuel pressure.

7.Contaminated fuel.

8.EGR valve that is leaking.

9.Oxygen sensors.

10.Throttle position sensor.

11.Manifold absolute pressure sensor

12.Mass Airflow Sensor

13.Idle air control valve

Note: If it doesn't apply disregard it-
Mar 16, 2012 at 12:35 AM
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