my 98 disco I had great gas mileage however my 99 disco II has horrible mpg. what is most likely my problem? fuel filter, plugs, wires....etc ? should I use some fuel additive or inejector cleaner?

 

Start with premium fuel, spark plugs, Magnecore wires, air filter, induction cleaning, intake cleaning and light foot.

Exactly what mileage are you getting?

 

Check the weight of your vehicle, if it is as heavy as most of our Discos, then you will get bad MPG--Also if it is not Diesel expect horrible mileage!

 

I did a combination ignition wire and oxygen sensor change and my gas mileage improved.

 

will fuel filter do anything for the MPG? also, when you say induction and intake cleaning, what exactly do you mean. I already use premium fuel and have a new air filter. I don't know the exact mpg since there is no trip computer but shouldn't the discos II get better mpg than discos I bc my disco I was much better

 

gas DII's do not have a fuel filter that can be changed (part of the fuel pump). any idea how man mpg you are getting with the DII, what did you get with your D1?

 

the disco II is getting low teens while the disco I was getting around 20mpg, so you're sayin that the fuel filter can not be changed and its most likely my plug and wires that's causing the problems? I understand the plugs but why do the wire matter so much if they're good? is it bc of the diamter of them or somthin? what's the diameter of the stock gray wire?

 

How in this universe did you get a DI to get 20 mpg? Mine will get 15 or 16 tops on a good day and it has had almost all major fluids and a few other parts changed within the last 3k miles. And that's downhill. Tailgating a tractor trailer. And with a back wind of 50mph. Well you get the idea :P

 

The D2 is heavier than the D1 because of the added weight from lengthening the body. The stock plug wires are 7mm which means they can't carry as much current as 8mm wires. Your O2 sensors could be causing bad fuel mileage.

 

What octane gas are you using, have you replaced your wires, when was it last tuned, how many miles on it and what additive are you using?