I just finished a 1500 mile trip. First since I owned the car.

It's a 2004 XJ8 with 96K miles.

I got 31 MPG on the highway, according to the computer. My tank fillups confirm.

I am elated and shocked. Full size luxury at economy price... can't beat it.

 

My XJ8L used to regularly get 28 combined and over 30 highway.

Then they forced the gasohol on us. Since the switch to gasohol, the XJ only gets 24-26. Every now and then I get a tank of straight gas, and the mileage goes back up...

 

It's easy to get up to 30 mpg on the highway, it is all those little trips around town that drink the h=juice, That and cold starts to move the car out of the way so I can get my MG TF out of the garage !!

Our recent holiday trip to Germany was 2840 miles and overall I got 28 mpg (UK gallons) driveway to driveway. Now its back to about 26.5 mpg.

 

Yeahppp! I usually get 29.5-31 mpg on the highway. As FM said, it's the city miles that differ, but technically, compared to my other cars, the city miles aren't too bad. Now saying all this, I made a trip to Kansas city, KS this past weekend, & coming back, I let someone else drive. He was gunning 85-95 the whole way, so my 29.5-31mpg went out the farkin window!!!

 

Last 1k mile trip was 31~32 MPG for me as well @ 70~75 MPH...

 

Visit pure-gas.org for a list of ethanol free stations.

 

I am assuming you folks are using premium fuel? best i have seen on highway rides is 28 US mpg

 

Try driving with the INSTANT FUEL GAGE on the Dash; It'll basically train you how to drive & get the numbers we speak of. That's what helped me @least...

 

I have noticed it always reset back to the odometer every time you start the car. Any way to prevent having to scroll down the sequence?

 

Nope!!! That is DEFINITELY one of the top pet peeves for me! Very whack!!!

 

well I guess the mileage isn't so shocking after all..... wonderful

I set the cruise at 72MPH on I75 and I81 between TN and PA

I always use premium gas, but just whatever's available, so usually gasohol
I also add a bottle of Lucas Oil to most tankfulls.... maybe it's snake oil, but I like the idea of keeping things nice and lubed up in the upper engine parts

 

I use Lucas as well, but after every 3 fill ups. I only use BP gas. (Just my preference) Sidenote: I'm from Tennessee as well.

FYI, I've been able to get 23.5 gallons on the tank by sift/slow pumping. I do the same in my RRS as well...

 

23.5 gallons, interesting... Mine has never gotten more than 18.5 gallons and that is even when the system says 0 miles to empty (eek!).


I am sure the empty setting leaves a gallon or so in there to assist with drudge not being sucked through the system from the bottom of the tank.

Does anyone else get 18 gallons per full fill up or is this only me?

P.S. BTW nearest Pure fuel gas station to me is 40 miles away. Not one single pure gas place in the whole of the Dallas/Fort Worth metroplex.

 

SHISK Trosty. That's definitely not rite!!! You should get @least close to 21.5 from 0 miles (I actually run mine down to 0 miles to empty a bit)

 

I was under the belief the X350's had a 85 litre usable capacity (or 84.5L for SC engines). That works out to 22.45US Gal for the normally aspirated engines. I'm not sure if that includes the filler neck, which might hold another Gal. If the gas station pump guage was correct, you must have literally been on fumes.


There have been a couple times over the years where according to the gas station pump guage I've put several more gallons of fuel in the tank than the official size of the tank - at least once this included a car that had no filler neck. It lead me to believe someone was trying to earn a little extra margin on the gas sales. I didn't buy gas at those stations again.

 

Hmm, Just checked my last fill up receipt and it says 18.255 gallons and I think I squeezed a little more in there to round out the receipt to $50 ($2.7397 per gallon).

I am going to fill a gas container with full (2.5 gallon) and then run the car to engine stall. Then fill up with the known amount from the can and then go fill up ans see what I get. I hate it when things aren't right like this.

A point of note though is I fill the vehicle until the pump handle cuts out using the stay bar and then no more. I used to fill until I saw fuel at the top of the fuel spout but people said all that is wasted as it flows out of the overflow pipe when you start to drive away (albeit this was on other cars).

 

Trosty, How much gas is normally left when you refill up? Like I say, I'm usually ruining mine down between 0-25 miles to empty...

 

Pretty much about the same for me. Of course, 25 miles equates to about a gallon anyway, so that would still only be 19.5 gallons from that sort of range remaining.

Anyway back to the thread, That's good mileage for these old 4.2 Litre V8 stonkers.

 

checked my driver's handbook.

Tank capacity 22.4 US gallons or 85 litres.
Fill Capacity (when fuel gauge indicates empty) is 20.9 US gallons or 79 litres
Reserve capaity (when fuel gauge indicates empty) is 1.5 US gallons or 5.8 litres.

 

All is good till you get just north of Harrisburg. Then it goes to crap LOL