How do you fix a random cylinder misfire detected?

You locate the cause of the random misfire and take corrective actions against that; be it a coil, plug, wire, coil boot or crank sensor. A random misfire is as it states - a misfire that happens randomly in possibly a random cylinder as well. They can be hard to diagnose, as well and it is recommended that you take vehicle to a qualified, ASE certified shop for diagnostics.