Report "2006 navigator 5.4 150,000 miles. Vehicle had a slight miss or shutter for the passed 30,000 miles but has gotten much worse. Got misfire on start up p316 p302 p306 etc. p171 left bank lean. Normal cop inspection, checked plugs, not new but not done either. Problem with. This is you start replacing all components of spark only to find they are secondary effect of the real issue. Bogs after full throttle pass. With light throttle pressure. Smell of exhaust comes in cabin without presence of an exhaust leak. Much condensation coming from tailpipe, not coolant just water vapors. Burning crayon smell at times? Poor and erratic acceleration without cel"