Truck has always run great. Got gas at Costco yesterday and as soon as I started it and got to the first stop sign, I could tell it was misfiring on some cylinders.....you could feel the twitch at idle. Runs ok normal driving. Took a look lunch break at work with the Tech 2.....live graph shows big time misses on #8. So now I think the gas at Costco was just a coincidence.....I will check the plugs when I get home...hopefully they aren't counterfeit iridiums from Amazon.