27th Aug 2007, 14:53

Well, 1 English (US) gallon is roughly.833 Imperial gallons.

Converting your 31 mpIg to US gallons I get roughly 25.8 mpUSg. That seems a bit high for a 5.0 Windsor unless you are going down a mountain with a 60 mph tail wind.

21st Nov 2007, 12:16

I agree that 30 Imp. MPG or more is realistic in the C.V. or Grand Marq. with the 5.0 Litre. Why would anybody use U.S. MPG's if they don't need to. I really should be talking L/100kms. Funny how the rest of the world is on the Metric System. It is nice to understand both as most do except the Americans. They are lost. Don't get me wrong as I remember when 55 MPH signs were here to in Canada. I was pissed when that changed to 90Km/H. But later in life one relizes how much nicer it is to work with SI.

26th Oct 2009, 04:48

I have 90 LX, and also got 31mpg on mine. How did I know it? I went several times to California and back. (60 mph on cruise control, nitrogen filled tires, 4 people aboard and some stuff in trunk, synthetics everywhere, removed Landau top for less drag)

23rd Aug 2010, 19:34

OK, seems I am a bit late to post, but I wanted to point out that my old 88 Town Car with the same engine but different rear diff ratio got 24.5 at or below 65 mph before the camshaft or lifters wore down at 300,000 miles. The lighter CV or Merc Marq with 2.73 instead of 3.08:1 ratio wouldn't have any trouble getting over 25 mpg. I had an aunt get 27-28 on a trip with hers but she was driving considerably faster than 65.

Another thing I wanted to point out is that gasoline is different from one region to the next. Canada may have completely different and perhaps more volatile fuel than we do. I know for a fact that the higher octane with increased anti-detonation product is readily available in Canada where it is not in the U.S. It makes a big difference! I live in SW MO and I get different mileage here than one of my uncles in St. Louis. They have a different gasoline there. Their cars ping more at lower miles because of the fuel. In the Carolinas the fuel is different and better than it is here in SW MO.

Synthetic oils are used much more frequently across our borders because unlike rich Americans who just throw away oil long before it's worn out, they don't have the luxury of doing such a thing, it is rather common to drive 10,000 to 25,000 miles or more on synthetics across our borders. Synthetics decrease resistance. Another reason for better mileage.

Don't insult the person without knowing all of the facts. It's not really worth raising blood pressure or writing something unpleasant. If he says he gets 31 mpg, then he gets 31 mpg. You don't have to believe, but to write something belligerent is unnecessary. I didn't believe my aunt either until I drove her car... I sure as heck didn't insult her, though!