P0171 on a 2013 Ram 1500

P0171 means the engine computer is adding more fuel than normal on bank 1 because it sees too much air or not enough fuel.

Not your vehicle? See general P0171 info.

Most common causes on the 2013 Ram 1500

Ranked from 1,254 NHTSA owner complaints filed for this vehicle.

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1
Camshaft and Lifter Failure (MDS System)
High severity
A known issue on the 5.7L Hemi where lifter rollers fail and damage the camshaft, leading to misfires, poor engine performance, and unbalanced air/fuel mixtures that can trigger lean codes. Confirmed by engine ticking, misfire codes, and physical inspection of the cam/lifters.
Reported in 10 NHTSA complaints
2
Exhaust Manifold Leak (Broken Bolts/Warped Manifold)
Medium severity
Broken exhaust manifold bolts and warped manifolds are extremely common on the 5.7L Hemi. An exhaust leak upstream of the O2 sensor pulls in oxygen, falsely reading lean and triggering P0171. Confirmed by a ticking noise on startup and visible broken bolts.
Reported in 6 NHTSA complaints
3
Faulty Oxygen (O2) Sensor
Low severity
A degraded or failing upstream O2 sensor can falsely report a lean condition. Confirmed by monitoring O2 sensor voltage switching and response time on a scan tool.
Reported in 1 NHTSA complaint
4
Clogged or Faulty Fuel Injectors
Medium severity
Restricted fuel injectors cannot deliver the commanded amount of fuel, causing a lean condition in specific cylinders. Confirmed by injector balance testing or observing misfires alongside the lean code.
Reported in 1 NHTSA complaint
5
Evap Purge Solenoid Leak
Low severity
A stuck open purge valve can introduce unmetered air/fuel vapors into the intake, sometimes causing a lean condition if it acts as a vacuum leak. Confirmed by testing the purge valve for leaks.
Reported in 1 NHTSA complaint
6
Vacuum Leaks (Intake Manifold Gasket, Vacuum Hoses, PCV)
Medium severity
A vacuum leak introduces unmetered air into the engine, causing a lean condition. Look for cracked hoses, a hissing sound, or high fuel trims at idle that improve at higher RPMs.
Common cause
7
Low Fuel Pressure (Failing Fuel Pump or Clogged Filter)
High severity
If the fuel pump is weak or the filter is clogged, the engine won't receive enough fuel, resulting in a lean code. Confirmed by testing fuel pressure with a mechanical gauge.
Common cause
8
Dirty or Faulty Mass Air Flow (MAF) / MAP Sensor
Medium severity
A dirty or failing sensor miscalculates the amount of air entering the engine, leading to insufficient fuel delivery. Confirmed by checking sensor data on a scan tool and inspecting for contamination.
Common cause

These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0171 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Rough idle
Hesitation
Surging idle
Poor fuel economy

What to check before replacing parts

Review short- and long-term fuel trims on bank 1

Look for: High positive trims (commonly worse at idle, improving with RPM) mean the computer is adding fuel to compensate for excess air or insufficient fuel — that pattern is this code's fingerprint.

Smoke-test the intake

Look for: Smoke escaping (or a hiss you can hear) at intake boots, gaskets, or vacuum hose connections confirms unmetered air is entering after the MAF sensor, which is the most common cause of a lean code.

Inspect the PCV hoses and valve

Look for: A cracked, split, or disconnected PCV hose, or a PCV valve stuck open, draws in extra unmetered air the same way a vacuum leak does.

Clean and test the MAF sensor

Look for: Visible dirt or oil film on the sensor element, or a grams/second reading that doesn't track expected airflow for RPM, means the MAF is under-reporting air and causing the computer to under-fuel.

Verify fuel pressure

Look for: Pressure below spec (weak pump, clogged filter, failing regulator) starves the engine of fuel and produces the same lean trim pattern as a vacuum leak — rule it out before chasing leaks.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Car Runs Rough