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2018 Charger SXT Rough Idle and Stalling - CEL P0171

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Ashley M. · rep 0 · May 22, 5:41 AM · 1 replies · solved · Question

Vehicle: 2018 Dodge Charger SXT

Hey everyone,

My 2018 Dodge Charger SXT, with the 3.6L V6 engine, has been acting up lately. For the past few weeks, it's developed a really rough idle, especially when I first start it up in the morning or when I'm stopped at a red light. It feels like it's struggling to stay running.

A couple of times, it's actually stalled completely when I've come to a stop, which is pretty concerning. After it stalls, it usually starts back up, but the rough idle persists.

The check engine light came on a few days ago. I had it scanned at an auto parts store, and it pulled a P0171 code, which I think means 'System Too Lean Bank 1'. I'm not super mechanically inclined, so I'm hoping someone here might have some ideas or experience with this.

Any thoughts on what could be causing this? Is it something I can check myself, or should I just take it straight to the dealer? Thanks in advance for any help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:41 AM

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ClearTheCode admin answer:

The P0171 code (System Too Lean Bank 1) on your 2018 Dodge Charger SXT, combined with a rough idle and stalling, strongly suggests that your engine is receiving too much air or not enough fuel on one side (Bank 1) of the engine. This can lead to poor combustion and the symptoms you're experiencing.

Here are the common causes and steps you can take:

  1. Check for Vacuum Leaks: This is one of the most frequent causes of a P0171 code.

    • How to check: Visually inspect all vacuum lines, PCV valve hose, intake manifold gaskets, and brake booster hose for cracks, disconnections, or signs of wear. A common trick is to spray a small amount of unlit propane or carb cleaner around these areas while the engine is idling; if the idle smooths out or changes, you've found a leak.
    • Why it matters: A vacuum leak introduces unmetered air into the engine, making the air-fuel mixture lean.

  2. Inspect Mass Air Flow (MAF) Sensor: A dirty or faulty MAF sensor can send incorrect air readings to the engine control unit (ECU).

    • How to check: You can try carefully cleaning the MAF sensor wires with a specialized MAF sensor cleaner (never use anything else). Ensure it's completely dry before reinstalling.
    • Why it matters: An inaccurate MAF reading can cause the ECU to inject less fuel than needed, leading to a lean condition.

  3. Fuel System Issues:

    • Fuel Filter/Pump: A clogged fuel filter or a weak fuel pump can restrict fuel delivery. While less common for a bank-specific lean code, it's possible if the overall fuel pressure is low.
    • Fuel Injectors: A clogged or faulty fuel injector on Bank 1 could be delivering insufficient fuel. This would typically be accompanied by misfire codes (P030x) if severe.
    • Why it matters: Insufficient fuel pressure or delivery directly causes a lean mixture.

  4. Oxygen Sensor (O2 Sensor): A failing upstream (pre-catalytic converter) O2 sensor on Bank 1 could be sending incorrect data to the ECU, causing it to lean out the mixture.

    • Why it matters: The O2 sensor monitors exhaust gases to help the ECU adjust the air-fuel ratio. A bad sensor can give false readings.

When to see a professional shop:

  • If you've checked for obvious vacuum leaks and cleaned the MAF sensor without resolving the issue.
  • If the problem persists or worsens, or if new codes appear.
  • If you suspect fuel system issues (pump, filter, injectors) or a faulty O2 sensor, as these often require specialized diagnostic tools and expertise to properly test and replace.
  • Continued stalling can be dangerous, so addressing this promptly is important for safety and to prevent potential long-term engine damage from running too lean.
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