See how our brains work. We fix these things in our heads. it's all an experience thing. My neighbor mechanic fixed my Acura on Wednesday. Started car, all the warning lights came on, missing real bad. I feared the worst. Smell of sulphur. Related this to my local guy 4 doors down. His answer, oh that's probably a bad coil on one of the cylinders. He started unplugging cylinders/coils one at a time till he found which one was bad/leaving connected made no difference in how the car ran. Swapped with known good coil and bingo confirmed which was the bad one. $58 for the part and $50 for labor I was back on the road. Ita all in the experience.