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FuelSeverity Medium: diagnose soon

P2187System Too Lean at Idle (Bank 1)

What it means

The mixture on bank 1 is too lean at idle and the ECU has reached its correction limit.

Symptoms

  • Rough or hunting idle
  • Check engine light

Common causes

  • Vacuum leak (most likely when it's only at idle)
  • PCV valve or hose leak
  • Leaking intake gasket

What to check first

  1. Smoke-test the intake
  2. Compare fuel trims at idle and at 2,500 rpm
  3. Check the PCV system
Can I drive with P2187? Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P2187: questions and answers

What does P2187 mean?

P2187: System Too Lean at Idle (Bank 1). The mixture on bank 1 is too lean at idle and the ECU has reached its correction limit.

What are the symptoms of P2187?

Rough or hunting idle. Check engine light.

What causes P2187?

Vacuum leak (most likely when it's only at idle). PCV valve or hose leak. Leaking intake gasket.

How do you diagnose P2187?

1. Smoke-test the intake 2. Compare fuel trims at idle and at 2,500 rpm 3. Check the PCV system

Can I drive with P2187?

Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.