Answer :
The precision measuring tool used to measure how well the cylinder in the engine is sealing is the "Cylinder leak down gauge."
Here's why:
1. **Cylinder leak down gauge:** This tool is specifically designed to assess the sealing ability of the cylinder in an engine. It measures the percentage of leakage from the cylinder, indicating the effectiveness of the cylinder's sealing capabilities.
It's important to note that while other tools like gap gauges, crankcase leak down gauges, and crankcase vacuum gauges serve different purposes in engine diagnostics, the cylinder leak down gauge is the most appropriate choice for evaluating the sealing integrity of a cylinder in an engine.