I recently went through inspection and I failed emissions because of an engine misfire. The codes are p0300, p0301, p0302, p0303, p0304, p0305, and p0306. With all six cylinders misfiring, I should not be able to drive my jeep. It runs fine, and I have been monitoring my MPG (about 20hwy). There are no acceleration issues, and the engine is not cutting out on me. What could be the problem??