P2187 on Ram vehicles
System Too Lean at Idle (Bank 1) — what it means on a Ram, whether it's safe to drive, and the fixes by model and year.
P2187 on a Ram means system too lean at idle (bank 1). Most vehicles stay drivable short-term, but diagnose it promptly. The most common cause is vacuum leak (intake gasket, brake-booster hose, pcv, throttle-body gasket) (typically $80–$600). Pick your Ram model below for its known failure patterns, recalls, and TSBs.
What does P2187 mean on a Ram?
P2187 is set when long-term fuel trim on Bank 1 goes excessively positive (typically beyond +20 %) specifically at idle, but stays closer to normal at part-throttle and cruise. The distinctive pattern — lean only at idle — almost always points at a vacuum leak rather than a fueling problem. At idle, intake manifold vacuum is at its highest, which amplifies the effect of any leak; off-idle, the leak path becomes a smaller fraction of total airflow and trims look fine.
P2187 is a standardized OBD-II code, so its definition is the same on every Ram. What differs by model and engine is which cause is most likely — pick your Ram model below for a diagnosis tuned to its known failure patterns, recalls, and TSBs.
Is it safe to drive a Ram with P2187?
In most cases a Ram stays drivable for short trips with P2187 active, but diagnose and repair it promptly. This is a moderate-severity code — ignoring it can lead to further damage or a failed emissions test. Exact tolerance depends on the model and engine.
What causes P2187 on a Ram?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Vacuum leak (intake gasket, brake-booster hose, PCV, throttle-body gasket) — P2187 is essentially "lean at idle = vacuum leak" until proven otherwise. | Most common | $80–$600 |
| Stuck-open EVAP purge valve introducing fuel vapor unmanaged | Common | $80–$300 |
| Cracked plastic intake manifold (Ford 4.6/5.4, Chrysler 4.0, GM 3.6) | Common | $250–$900 |
| Failing PCV valve or hose | Common | $30–$200 |
| Failed or biased Bank 1 upstream O2 sensor | Occasional | $150–$450 |
| Throttle body gasket leak | Occasional | $30–$200 |
| Carbon-coked throttle body letting blade hold slightly open | Occasional | $20–$200 |
Repair costs are typical US ranges and vary by Ram model, model year, and labor rate. A diagnostic trouble code is a symptom, not a guaranteed failed part — confirm the root cause before replacing anything.
P2187 by Ram model
Select your Ram model and year for a P2187 diagnosis tuned to that vehicle's failure patterns, recalls, and TSBs.
Ram 1500
1,537 NHTSA owner complaints · 35 recalls on record across the years covered below.
Complaint and recall counts are NHTSA totals for the model years covered on this site, not counts specific to P2187.
P2187 on other makes
Other codes on Ram vehicles
P2187 on a Ram: frequently asked questions
What does diagnostic trouble code P2187 mean on a Ram?
P2187 is set when long-term fuel trim on Bank 1 goes excessively positive (typically beyond +20 %) specifically at idle, but stays closer to normal at part-throttle and cruise. The distinctive pattern — lean only at idle — almost always points at a vacuum leak rather than a fueling problem. At idle, intake manifold vacuum is at its highest, which amplifies the effect of any leak; off-idle, the leak path becomes a smaller fraction of total airflow and trims look fine. P2187 is a standardized OBD-II code, so the definition is the same on every Ram — which cause is most likely varies by model and engine.
What are the symptoms of P2187 on a Ram?
Check Engine Light is illuminated. Rough or unstable idle, especially when warm. Possible hesitation or stumble immediately off-idle. Stalling at idle (worst cases). Slight reduction in fuel economy. May be paired with P0171 (general lean Bank 1) if the leak is large. No drivability issue at cruise
What causes P2187 on a Ram?
Vacuum leak (intake gasket, brake-booster hose, PCV, throttle-body gasket) (most-common). Stuck-open EVAP purge valve introducing fuel vapor unmanaged (common). Cracked plastic intake manifold (Ford 4.6/5.4, Chrysler 4.0, GM 3.6) (common). Failing PCV valve or hose (common). Failed or biased Bank 1 upstream O2 sensor (occasional). Throttle body gasket leak (occasional). Carbon-coked throttle body letting blade hold slightly open (occasional)
Is it safe to drive a Ram with P2187?
In most cases a Ram stays drivable for short trips with P2187 active, but it should be diagnosed and repaired promptly — this is a moderate-severity code. Ignoring it can lead to further damage or a failed emissions test. Exact tolerance depends on the model and engine.