Posts Tagged: misfire troubleshooting
The Smart Way to Diagnose an Engine Misfire
How to Diagnose an Engine Misfire Step by Step Quick Summary The ECM detects an engine misfire by monitoring the crankshaft position sensor. It knows when it commanded the plug to fire and then monitors crankshaft speed to determine whether it increases. If the cylinder misfires, the crankshaft will slow because the cylinder has failed to contribute its share of power. That failure can be momentary or constant, isolated to one cylinder or spread across several. Regardless, every engine misfire has a root cause, and finding it requires discipline, not … Read More
What Causes a Cylinder Misfire in Modern Engines
The Most Common Causes of a Cylinder Misfire Quick Summary A cylinder misfire happens when one or more cylinders fail to complete a proper combustion event. In my experience, the most common causes of a cylinder misfire fall into four categories: ignition problems, fuel delivery issues, unmetered air or vacuum leaks, and internal mechanical failures. Misfire trouble codes—especially P0301-P0308—tell you where to look, but not why the misfire is happening. Proper diagnosis means working methodically, not firing the parts cannon. In this article, I’ll walk you through how I diagnose … Read More