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2017 Malibu 1.5T Loss of Power & Misfires

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Emily N. · rep 0 · May 22, 2:32 AM · 1 replies · solved · Question

Vehicle: 2017 Chevrolet Malibu LT 1.5T

Hey everyone,

I'm having a frustrating problem with my 2017 Chevrolet Malibu LT, 1.5L turbo. Recently, I've noticed a significant loss of power, especially when accelerating. It feels sluggish, and sometimes I hear a faint whining noise that wasn't there before.

To make things worse, the check engine light came on, and the car started to misfire, particularly under load. I had the codes read, and it's showing P0301 (Cylinder 1 Misfire Detected) and P0299 (Turbocharger/Supercharger Underboost Condition).

What could be causing both a misfire and a turbo underboost simultaneously? Could they be related? Any advice on where to start troubleshooting would be great!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:32 AM

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ClearTheCode admin answer:

The combination of a P0301 (Cylinder 1 Misfire) and P0299 (Turbocharger/Supercharger Underboost) on your 2017 Chevrolet Malibu 1.5T suggests a few potential interconnected issues. These codes are definitely related and point towards a problem affecting both combustion and turbo performance.

Common Causes:

  1. Spark Plugs/Ignition Coils: A failing spark plug or ignition coil in cylinder 1 would cause the P0301 misfire. This misfire can also impact exhaust gas flow to the turbo, potentially contributing to the underboost condition.
  2. Fuel Injector Issues: A clogged or faulty fuel injector for cylinder 1 could cause the misfire. If the engine isn't getting proper fuel, it won't produce enough exhaust gas to spool the turbo efficiently, leading to underboost.
  3. Turbocharger Wastegate/Actuator: A stuck open wastegate or a faulty wastegate actuator can prevent the turbo from building sufficient boost, triggering P0299. This could also indirectly affect engine performance and lead to misfires if the air-fuel mixture is too lean.
  4. Boost Leaks: Leaks in the intake system (intercooler, hoses, clamps) after the turbo can cause a loss of boost pressure, resulting in the P0299 code. A significant leak could also lean out the air-fuel mixture, potentially causing misfires.
  5. Catalytic Converter Restriction: A severely clogged catalytic converter can create excessive back pressure, hindering the turbo's ability to spool and causing general engine performance issues, including misfires.

Diagnostics & When to See a Shop:

  • Inspect Ignition Components: Start by inspecting and potentially replacing the spark plug and ignition coil for cylinder 1. Swapping components with another cylinder can help confirm if the issue moves.
  • Check for Boost Leaks: A smoke test of the intake system can quickly identify any leaks.
  • Fuel System Test: Check fuel pressure and injector performance.
  • Turbocharger Inspection: A mechanic should inspect the turbocharger for shaft play, wastegate operation, and any signs of damage.
  • Professional Diagnosis: Given the complexity of turbo engines and the interplay of these codes, a professional diagnosis is highly recommended. They can use specialized tools to monitor boost pressure, fuel trims, and misfire counts in real-time to accurately pinpoint the root cause.
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