My 2012 threw a P0308 code at just over 100,000 miles. After researching and finding out that the three most likely culprits were spark plug, coil pack or vacuum leak I decided to tackle the spark plug first. I replaced all of the stock plugs with NGK iridium plugs that have a standard electrode. I switched number 8 and number 1 coil packs in case the plug wasn't the problem. The old plugs look fine to me, but then I've never seen the tiny two piece electrode before, so I don't have anything to judge it by. The ground electrodes all looked good and the insulators tip all had a slight brown tint. Long story short the truck now runs fine and the cleared code has not returned. It could be just my imagination but the truck seems down on power at full out acceleration yet idles smoother than ever?