Good write up, Bruce. Enjoyed reading it.
My 3.0L auto average 22mpg during summer, 25mpg in spring and fall and 23 in winter. I think it's mostly function of A/C and defrost/headlamp usage that affect my mileage. And if I'm on highway, I try to use the cruise control as that also raises fuel economy.

 

Mine is a 2.5L manual. Don't know what I'm getting in town, but on the highway it's 29.x and I do like to run the air conditioner.

 

21-22 mpg freeway & city mixed. 2002 3.0

 

I just did a run from Vancouver, Canada to the San Francisco bay area last weekend.

1,970.5 total miles
62 MPH average speed (per GPS)
128 MPH max. speed (per GPS)
24.66 MPG (US) average (hand calculated)

Trip included stop and go traffic in a few spots plus some running around town while in California. Overall very impressive given the speed (I wasn't running for mileage but was curious. lol)
Car is 2005 3.0 with 5 spd manual, AC on.

 

Hey Fellas,

I just bought a 2002 X-Type 2.5L manual and I get 23 avg. Mixed driving. Mine is a sport with 17inch wheels. Today I checked the spare tire to make sure it was ready if I need it and I was happily surprised to find a full size spare on a 17inch wheel that matches the others. Cheers to the fine chaps at Jaguar!

 

Average over 10 months is 24 mpg

 

Honestly I wouldn't use it except for a 10 mile trek to get out of harms way. AWD and different diameter tires or different tread patterns is not a good combination. Having a manual tranny makes you a little safer but you will heat that tranfercase up quite a bit.

 

I have a X-Type 2.0D Manual 2003.
The following picture is the highest MPG I achieved. I had just filled up £5 diesel and went onto the dual carriageway and thought I would test how high I could get this as usually the way I drive on local roads I end up with about 20 mpg as I am always driving fast. Any way the following MPG I got driving about 50-70mph. I swear I would have got higher but then I had to slow down which is when I got the chance to snap that shot and thats why its showing I am doing about 40mph. For those who have difficulty reading it, it says 57.4 MPG!

 

I get 18.9 mpg with my 3.0L but on the highway i get about 26 to 28 mpg. I love this thing on the highway.

 

I'm flabbergasted. Got the car 1-1/2 weeks ago. Got 28 MPG with my first tank in mixed driving and about the same (need to fill up tomorrow to confirm) in 70+ MPH trip (280 miles) today. I had it figured for maybe 25 MPG. This is FABULOUS news!

Now, if I could just get rid of this stupid code that keeps popping up.

 

So I used to get around 18 MPG then I added a Chevron Techron Solution that is supposed to clean up the fuel system. Now I'm acctually at 19.1 MPG. It says you can use it a second time for improved results or every 3000 miles. It worked for me so if you guys are trying to improve a little, I would say give it a shot. Chevron puts techron in their gas which is supposed to clean out the engine over time. I just went the faster route since I really only buy gas from Costco.

 

Update:

Filled up today and got 26 MPG over the 300+ miles I traveled, most of that was over 70 MPH. Running at 3k+ RPM is too high, though. This car should have been equipped with a six speed trans ... with sixth gear dropping the RPM down to about 2600/2700 at 73/74 MPH. That would allow larger throttle openings and improve efficiency. I'm sure the car would see all of 28 MPG then. VERY nice for a car this size.

Oh, well. It is what it is.

 

My 2.5L automatic gets 24 mpg on my 22 mile commute (mixed city/highway), and 29 mpg on a road trip.