My average miles per gallon on a 2000 DII (4.0 L) has been 15 MPG (reg unleaded) for the last 60 K Miles. The driving cycle is split city traffic / interstate.

The laws of physics and internal combustion efficiencies will not allow a 16 MPG city driving. It is just not possible, well unless the city has one traffic light and a vehicle population of 20 and all the roads are level and the temperature stays at 72 F and speed limit is 35.

I saw in other posts that folks are getting 20 MPG, that is impossible with the V8 gas. I am assuming they all have diesel engines and not the V8.

It will help you mileage if your ignition / intake / injection systems are in top shape. Also, if your compression is right and you use synthetic fluids (less rotating resistance) and you keep your tires inflated (I run 36 PSI all around).

One last point on mileage: Use your lockup torque converter function to your advantage, it will improve your MPG by 10 to 15%. Try to stay in lockup mode as much as you can by keeping a steady foot on the gas pedal and your speed slightly above 35, where you can.

If an explanation is needed on the lockup torque converter function and how it saves gas let me know.

 

People talking about 16 mpg, are talking highway mileage. 11-13 is the normal range for city driving with morning and evening trafficon a disco. There's no point in spending upwards to $200-$300 for wires and plugs and induction cleaning to get an addititonal m.p.g, it will take you years to get your money back, let alone profit from it.

If you were getting 8-9 m.p.g, I'd look for improvement, but 12.5 in city driving is dead on on a Disco. Brand new, the window sticker says exactly that !!

But Unimoged.....what the heck is that lock-up thing on the converter ?????

 

I am averaging around 13.5 mpg with 80% city driving. I am usually the last one stopping at the next red light. I laugh at all the vehicles that zoom around me between red lights. I have to go through 15 traffic lights to get to the local highway 7 miles away.

 

i once drove a rover out the back of a cargo airplane at 35,000ft. with the engine at idle and falling i only managed to get about 12mpg,,,HA!!!

 

You guys can say what you want but I have done the math more than once.
As a daily driver I average 15 mpg using Shell 93 octane.
On 2 700 mile round trips to Clevland last summer we got 24 mpg.
I drove truck for 13 years, I know how to anticipate stop lights, I am the last one up to speed, I use the cruise control like my life depends on it, speed limit is 35, set the cruise at 40.
I never drive faster than 65, windows up and sun roofs closed, no roof rack, stock sized tires at 40psi, no extra weight in the truck.
A well tuned/maintained/cared for Disco will get good mpg.
And I agree with unimog, use the tourqe convertor to your advantage.
Darover-the tourqe convertor is how the engine transfers the power to a automatic transmission, it is wasted energy becasue it is full of transmission fluid and the engine has to spin that fluid before it turns the transmission.
When the t-convertor "locks up" it is the same as a clutch, locked to the engine thus getting better MPG.
I am sure unimogged will explain it better than I.

 

I just found some 93 Octane Fuel...

But let me tell you.. They were PROUD of it..
a full $1.00 above the 91 Octane per Gallon..

We have had pretty low Fuel Prices lately so I went ahead and filled the tank..
Just to see..

Ill let you know in a week or so if I can duplicate Spike's 15 MPG

 

Unimoged, please do tell me more about the locked torque converter!

 

Before we get into the lock-up torque converter function, I would like to highlight a great point that Spike555 makes on tire inflation. Running tires at 40 PSI reduces rolling resistance and tire tread temperature, increasing MPG. My tires are at 40 PSI front and rear when doing a lot of interstate driving at 80+.

The lockup clutch in the torque converter basically allows your disco to operate as if it had a manual transmission, thus transferring 100% of your engine RPMs to the wheels, at speeds above 35 mph. If you keep a steady speed and a calm right foot, it will stay engaged, giving better gas mileage.

In depth explanation For tech. geeks like me: http://en.wikipedia.org/wiki/Torque_converter

 

I was able to achieve 21 mpg with granny driving and oversized nitrogen filled tires. 265/65 18 I replaced my plugs and wires with Magnacores and Bosh +2 since then and the very best I can do is 19 mpg.

 

Thanks all, I am taking a winter adventure to ID/ MT for some fly casting next week and will report back on the improved mileage, I hope. I just have to get the truck back from my mechanic by Wednesday or I will be taking the BMW...