yes it will prevent the flow of power, thus limiting the the voltage leaving the coil to reach it to the plug....my suggestion, a new set of wires, & be sure to use a di-electric grease when you put them on......
Heres the numbers. The go from max, gross polluter, and my numbers. 15 and 25 mph tests. The truck was smoking badly during the test. My gas mileage also sucks, 12-13 mpg.