P0301 GMC Terrain
Cylinder 1 Misfire Detected · Powertrain Code · High · Repair: Easy
What is P0301?
Misfire detected in cylinder 1. Typically caused by a worn spark plug, bad ignition coil, faulty fuel injector, or low compression in that cylinder.
When the GMC Terrain triggers code P0301 (cylinder 1 misfire detected), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the GMC Terrain.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your GMC Terrain.
Common Causes on GMC Terrain
- Ignition coil failure on cylinder 1 on 1.5T or 2.0T Ecotec
- Spark plug fouled from oil consumption on 2.4L Ecotec engine
- Fuel injector deposit buildup on GDI engines causing poor spray pattern
- Vacuum leak at intake manifold gasket near cylinder 1
Symptoms
- Rough idle with noticeable engine vibration
- Engine shaking or vibration especially at idle
- Loss of power during acceleration
- Check engine light flashing (indicating catalytic converter damage risk)
- Poor fuel economy from unburned fuel
- Unburned fuel smell from exhaust
Notes for GMC Terrain
GDI engines are prone to injector deposits; consider fuel system cleaning as preventive maintenance.