TRQ 6pc Ignition Coil Set of 6 Kit for Lexus GS300 GS350 GS450H IS250 IS350. Ignition Coil Features & Benefits. The ignition coil is a crucial part of your ignition system. It's function is to convert the 12 volt power of your vehicle's electrical system in to 35,000 or more volts. This produces a high intensity spark at the spark plug which then ignites the fuel in the cylinder. Coils in general will wear out over time and cause a misfire condition. In engines like this that use a coil, if the coil goes bad, the complete assembly needs to be replaced. Enough for one 6 ...