The After-Sales Problems Caused by Low-Quality Spark Plugs Are Greater Than You Think

Ever had trouble caused by low-quality spark plugs?
Carbon buildup, electrical leakage, misfires, complaints, and returns.
For distributors, the more after-sales issues there are, the harder it is to earn customer trust.
A reliable product helps avoid unnecessary trouble.
What's the most frustrating after-sales problem you've dealt with?