Mr. Engineer,
Mr. Engineer,
With your qualifications and a being a graduate of combustion engine design, how could you not know that the 250 and 350 motors are not one in the same? More to the point, the difference in the "design" and delivery of the fuel injection system of these motors. The grade of fuel is an unrelative and non issue respective to the cause and effect respective to the carbon build up surrounding the valves on the problematic 250 series. "Boom." You are fortunate to be driving a 350 otherwise, you to would be paying $600.00 for a top end cleaning every 7-10,000 miles had you chosen a 250. For those with a is250 year 2007-2011 there does in fact exist a fix.