The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2020 Acadia Engine Misfire - Check Engine Light Flashing

0

Mike T. · rep 0 · May 25, 2:36 AM · 1 replies · solved · Question

Vehicle: 2020 GMC Acadia SLT

Hi everyone,

I'm having a serious issue with my 2020 GMC Acadia SLT. The check engine light started flashing yesterday, and the engine is running really rough, almost like it's going to stall. It feels like it's losing power, especially when I try to accelerate.

I managed to get it home, but I'm hesitant to drive it much further. The flashing light usually means a severe misfire, right? I'm hoping it's something simple like a spark plug, but I'm worried it could be more serious.

Has anyone else experienced a persistent engine misfire with a flashing check engine light on their 2020 Acadia? What was the cause and what was the fix?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:36 AM

0

ClearTheCode admin answer:

A flashing Check Engine Light (CEL) on your 2020 GMC Acadia indicates a severe misfire that could potentially damage the catalytic converter due to unburnt fuel entering the exhaust system. It's crucial to address this promptly.

Possible Causes of Engine Misfire:

  1. Failing Spark Plugs: Worn or fouled spark plugs are a common cause of misfires. They might not be igniting the fuel-air mixture effectively.
  2. Faulty Ignition Coils: Each cylinder typically has its own ignition coil. If a coil fails, it won't provide the necessary spark to the plug, leading to a misfire in that cylinder.
  3. Clogged Fuel Injectors: A fuel injector that isn't delivering enough fuel, or is completely clogged, will cause a lean misfire in that cylinder.
  4. Vacuum Leaks: Leaks in the intake manifold or vacuum lines can introduce unmetered air into the engine, disrupting the air-fuel ratio and causing misfires.
  5. Compression Issues: Less common, but low compression in a cylinder (due to worn piston rings, valves, or head gasket) will also cause a misfire.

Diagnostics & OBD Codes:

  • A flashing CEL almost always means a P030X code will be stored, where 'X' is the cylinder number (e.g., P0301 for cylinder 1, P0302 for cylinder 2, etc.). A P0300 indicates a random/multiple cylinder misfire.
  • Other related codes might include P0171/P0174 (System Too Lean) or P0420/P0430 (Catalyst System Efficiency Below Threshold) if the misfire has been ongoing.

What to Do:

  1. Minimize Driving: Avoid driving the vehicle as much as possible to prevent damage to the catalytic converter.
  2. Scan for Codes: Use an OBD-II scanner to read the specific misfire code(s). This will tell you which cylinder(s) are affected, narrowing down the diagnostic process.

When to See a Shop:

  • Immediately. Given the flashing CEL and rough running, it's best to have your Acadia towed to a reputable mechanic or dealership. They can accurately diagnose the root cause using specialized tools and perform the necessary repairs, whether it's replacing spark plugs/coils, cleaning/replacing injectors, or addressing other engine issues.
Menu

Help & account