How much does it cost to fix P2187?

DIY repair typically costs $5–$100 for parts. Professional repair runs $80–$400 including parts and labor.

P2187

Powertrain

Low

System Too Lean at Idle - Bank 1

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Code P2187 indicates that Bank 1 of your engine is running too lean specifically at idle. This means the air-to-fuel ratio has too much air (or not enough fuel) when the engine is idling — sitting at a stoplight, in park, or any time you're not pressing the gas pedal. The code is an important diagnostic clue because it narrows the problem to idle conditions specifically.

A lean condition at idle often points to a vacuum leak, since even a small leak represents a significant percentage of the total air entering the engine at idle. At higher RPMs, the same leak becomes proportionally insignificant. Common leak points include vacuum hoses, the PCV valve, intake manifold gaskets, and the brake booster line. Another very common cause is an EVAP purge valve that's stuck open, which continuously introduces unmetered air into the intake.

You can often diagnose this yourself by carefully listening for hissing sounds around the intake with the engine idling, or by spraying a small amount of carburetor cleaner around vacuum connections — a change in idle speed indicates you've found the leak. The repair is usually inexpensive, involving a new hose, clamp, or purge valve.

Severity

Moderate — Address SoonThis Month

Symptoms

•Rough or unstable idle that feels like the engine is hunting
•Engine may stall at idle, especially when cold
•Slightly reduced fuel economy
•Check Engine Light on
•Occasional idle surging or fluctuation

Likely Causes

Small vacuum leak near the intake manifold35%

A minor vacuum leak from a cracked hose, loose clamp, or degraded intake manifold gasket lets small amounts of unmetered air in, which is most noticeable at idle when overall airflow is low.

EVAP purge valve stuck open25%

A purge valve that sticks open allows fuel vapors and air from the charcoal canister to flow into the intake continuously, leaning out the idle mixture. This is a very common cause of idle-only lean codes.

Dirty or failing fuel injectors20%

Injectors that are partially clogged or have degraded spray patterns may not atomize fuel properly at the low pulse widths used during idle, resulting in a lean mixture.

Weak fuel pump or low fuel pressure20%

A fuel pump with marginal output may maintain barely adequate pressure at idle, and any additional factor (hot fuel, low tank level) can push the mixture lean.