Originally Posted by BNotrab
1998, 4.0L, 130K, 2" OME, 245/75/17 BFG
The boss (wife) told me the other day she didn't seem to be getting as many miles to a tank as normal. Plan on changing the O2 Sensors (NTK), and Sparkplugs (AP985).
Anything else I should look into doing? All fluids are changed regularly.
You should caculate the current MPG.
Here is how I did mine:
First thing to do is use a GPS and determine if your speedometer is accurate and if not the percentage it is off.
Now, fill the gas tank, record the odometer reading (or reset the trip odometer to Zero)
Drive the jeep until it is low, approx 1/8 tank.
Fill the tank and record the exact number of gallons it took to fill it.
Record the odometer reading and subtract the beginning mileage from it (or record the number of miles on the trip odometer)
Divide the number of miles driven by the number of gallons it took to fill it back up. DO NOT omit the tenths if there were any.
Now do this a number of times and average it out.
If your speedometer is off multiply the number of miles driven by the percentage it is off and add it to the number of miles driven before dividing by the number of gallons.