Posts Tagged: low vacuum causes

How to Use a Vacuum Gauge to Diagnose Engine Problems

How to Test Engine Vacuum and a Vacuum Gauge to Diagnose Engine Problems Quick Summary When you know how to test engine vacuum and how to use a vacuum gauge properly, you can spot worn rings, valve problems, timing issues, and even a plugged catalytic converter in minutes. A healthy engine will typically pull around 18–22 inches of vacuum at idle. But what really matters isn’t just the number—it’s how steady that needle is and how it reacts when you change engine speed. A steady needle tells me the whole … Read More