Answer to "How many miles to add to total miles when idling"No 1 gallon per hour = to what ever you get per gallon 7 miles per gallon is going.g to be 7 miles. Period...
Answer to "Air Conditioning Works While Parked But Not While Driving, Why?"Have you checked you cab filter.
Answer to "2007 freightliner century class"Around 13.25 to 14.00 at 60 mph. rear ends ??? Transmission ???