Fill your tank and reset your trip odometer. When you fill up the next time divide the mileage from your trip odometer by the gallons needed to fill your Disco back up. My last fill up was 297 miles/19.4 gallons=15.3 mpg. I drive with a light foot and only used the A/C about a fourth of the tank. I laugh at all the people that race around me only to brake hard at the next red light.

 

i use 93 OCTANE and dont use any fuel additive, should I and what kind? But wouldnt the CHECK ENGINE light come on if the o2 sensors were bad. So 8mm WIRES are a must, are you saying that if I get new 7mm wires, that there is NO point of better MPG since the stocks are 7mm or will it still matter? ALso, how does an 8mm wire make that big of a difference in the MPG and what if I just changed the plugs to the BOSCH +4 and left the stock wires alone, will that help?

 

the 8mm wires will be able to carry a hotter spark giving you a more complete burn which translates into better fuel mileage. I prefer an iridium plug instead of a +4 plug.

 

Back to my original questions, how many miles on the truck and when was it last tuned???

 

120k and my guess would be never tuned since the wires are gray, so BOSCH +4 or iridium BOSCH? Also, will getting a NEW 7mm wire make a difference or will ONLY getting an 8MM plug make a difference? and what if i just changed the plugs and NOT the wires, will that make a difference

 

I like the NGK iridium. If you have original wires/plugs you need both new wires and new plugs. Just changing one or the other will not help very much.

 

VikingDiesel, either plug will work great. I use and love the +4's, but I'll be trying the Iridium plugs next change to see if I can find a significant difference. Most people I've heard from can't find a huge difference but love both. For the plug wires just grab 8mm Magnecore wires. Nothing else. They're your best option and they're not too pricey if you find a good deal. DiscoMike can hook you up with a good place to get them from.

 

You ask for help so quit back peddling, 8 mm Magnacors are they wire to use, not 7 mm's.
I have run both Plus 4's and the newer Bosh Fusion, I felt an immediate drop in power aafter removing my Plus 4's and installed the Fusions. My belief is for the extra cost, I would not recommend going to a more high performance plug that our engines can't take advantage of anyway.

 

ok, so BOSCH +4 it is, anyone know where i can get the MAGACORE wires thats NOT online, discomike i believe told me PEPBOYS, but maybe it was for something else. So when I do change the plugs and wires, should I then notice an MPG increase

 

Along with all of this work that is long since past due.

1 Oil filter, K&N 3001 or Mobil 1- 301
1 Factory air filter
6 Qts. of engine oil
2 feet of 3/16th vacuum tube
2 feet of 5/16th vacuum tube
12 Qts. of ATF
7 Qts. of 80/90W synthetic gear oil, 85W/140 for HD use
3 Pints of synthetic DOT 4 Brake fluid
2 Qts of synthetic Power steering fluid
2 Gallons of OAT, orange coolant, also called DexCool
1 Bottle of Lucas Power Steering additive
1 Bottle of Lucas Transmission additive
1 Can of Spray Carb. Spray
1 Can Of Brake cleaner
8 Spark Plugs, I use Bosch Platinum Plus 4's
1 Set of Magnacor 8mm plug wires
1 Serpentine belt
2 Bottles of SeaFoam gas additive
1 T/Stat
1 bottle of WaterWetter or Purple Ice
Hoses and belts, as necessary

60,000 Mile Service or Major Service for High Mileage Used Vehicle just purchased

Bleed the brakes
Flush and change the power steering fluid adding one bottle of additive
Service the tranny adding one bottle of additive
Change the coolant and t/stat
Do an engine flush before changing the oil
Do an induction cleaning
Clean the throttle body
Add fuel additive to full gas tank
Change both of the diffs fluid
Change the t/case oil
Replace the plugs and wires
Replace the air filter
Lube all the drive shaft grease fitting including the 2 slip shafts
Do full inspection of brakes, hoses, bushings etc.

Hopefully I didn't leave anything out.