On cylinder #1 in my truck in my signature, I have to change that plug every 2-3k miles. That cylinder burns a ton of oil and the plug fouls quickly. Once I feel a few misses, I change it. EVERYTIME I install a clean plug in that cylinder, the truck idles poorly and misses in cylinder for a minute. Then, she smoothes right out and runs like a top for another 2-3k miles. Why does it miss with a freshly cleaned plug?