P0171 on a 2020 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 2020 Ram 1500

Ranked from 613 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Weak or failing fuel pump (including EcoDiesel HPFP recall)
Medium severity
Two owners had high-pressure fuel pump failures (one recall-related) that reduced fuel delivery enough to affect running condition.
Reported in 2 NHTSA complaints
Parts:fuel pump
2
Intake manifold gasket / vacuum leak
High severity
One owner's truck needed the intake manifold itself replaced to resolve a persistent check-engine condition — a leaking intake manifold gasket is a direct, well-known lean-code cause.
Reported in 1 NHTSA complaint
Parts:intake manifold gasket
3
Faulty fuel-system valve causing lean running/stalling
Medium severity
One owner had a mechanic 'fix a valve' in the fuel system after a strong gas odor, only for the truck to develop hard starting and stalling/jerking days later — consistent with an unresolved fuel-delivery/vacuum fault.
Reported in 1 NHTSA complaint
4
Vacuum leak from cracked hoses or connectors
Medium severity
A split vacuum or PCV hose lets in unmetered air, leaning out bank 1.
Common cause
5
Dirty or failing mass airflow (MAF) sensor
Medium severity
A contaminated or drifting MAF under-reports intake air, so the PCM adds less fuel than needed.
Common cause
Parts:mass airflow sensor
6
Stuck-open PCV valve
Low severity
A PCV valve stuck open pulls extra crankcase air into the intake, leaning the mixture.
Common cause
Parts:pcv valve
7
Exhaust leak upstream of the front O2 sensor
Low severity
An exhaust leak ahead of the sensor draws in outside air, making the sensor read leaner than actual.
Common cause

Part links go to Amazon search results for this vehicle. As an Amazon Associate, WrenchConnect earns from qualifying purchases — always confirm fitment for your exact trim and engine before ordering.

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