Wells Vehicle Electronics rotor distribute voltage to the correct tower of the distributor cap, related to ignition timing. When the rotor is not replaced, the vehicle may misfire, experience high fuel consumption, Check Engine Light (CEL) illumination or no start - be sure to check the distributor cap when replacing the rotor. Wells Vehicle Electronics rotor is designed to meet or exceed Original Equipment (OE) specifications in form, fit, and function. Every component either matches or improves on the OE design to ensure fast, easy installation, superior performance and reliability.