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Jeep Grand Cherokee 1999-2004: How to Maximize Your MPG

For a Jeep, the Cherokee tends to fall in the middle of MPG for vehicles in this class. There are ways to maximize your MPG that won't cost a thing and simply require you to change how you drive.

By William Henderson - August 28, 2015

This article applies to the Jeep Grand Cherokee WJ (1999-2004).

According to the U.S. Department of Energy, Jeep Cherokees with automatic transmission get 16 MPG in the city and 21 MPG on highways. Also, Jeep Cherokees with manual transmissions do a bit better, getting an average of 18 MPG in the city and 23 on highways. But just because your Cherokee should perform like, this doesn't mean it does. Here are some tried and true ways—that won't break the bank—for improving your fuel economy.

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Step 1 – Follow the speed limit

Do not drive faster than the posted speed limit. You maximize fuel economy by driving at the lowest speed possible, in which the transmission can be in top gear. Obviously, going 45 on the freeway isn't a good or safe idea, but try sticking to 65 on the interstate versus cruising at 75 or 80. Fuel economy drops off exponentially as your speed increases. On highways, consider using cruise control (if your Cherokee is equipped with it). This will help you maintain a constant speed.

Figure 1. Following the speed limit can help improve your fuel economy.

Step 2 – Drive more efficiently

Keep the following tips in mind to maximize your Cherokee's MPG:

  • Slowly accelerate and avoid heavy braking. Rapidly accelerating and hard braking wastes fuel, which lowers your fuel economy.
  • Remove anything in your Cherokee that you don't need. The heavier your vehicle, the lower your fuel economy. Anecdotally, every 100 pounds you carry reduces your fuel economy by an average of one MPG. This doesn't seem like a lot, until you start adding up this one MPG reduction over multiple trips.
Figure 2. The heavier your vehicle, the worse your fuel economy.
  • Do not idle any longer than necessary. If you must wait somewhere, then simply turn off your Cherokee. For each hour you idle (and not even necessarily all at once), you waste between one-quarter and one-half gallon of gas.

Step 3 – Perform routine maintenance

Perform routine maintenance to help maximize your fuel economy. Routine maintenance includes:

  • Perform a tune up, which can help improve your fuel economy by as much as several MPG. Resolving serious issues can increase your fuel economy by even more. For example, some Cherokee owners report their fuel economy improving by around 40 percent after they've replaced a faulty oxygen sensor.
  • Properly inflate your tires and keep them properly inflated, which can improve your fuel economy by as much as 2-3 MPG. To find out the proper tire pressure for your Cherokee, look on the sticker that is located on the inside door jamb of your driver's door, or in your owner's manual. If your tires are under-inflated, you risk reducing your fuel economy by as much as 1-2 MPG, due to the increased drag.
Figure 3. Check your tires' pressure every month or so to make sure they remain properly inflated.
  • Use the right grade of motor oil when you change your oil. If you use a substantially heavier weight of oil than what Jeep recommends, you risk reducing your fuel economy by as much as 1-2 MPG.

Step 4 – Plan ahead

Bundle several trips together, instead of making several shorter trips over the span of a couple of days. Making several short trips over the course of a few days will reduce your fuel economy more than if you had combined these trips into a single afternoon. The more traveling you do when your engine is warm, the better your fuel economy.

Step 5 – Improve fuel economy in cold weather

Keep these tips in mind during the winter, which can help improve your fuel economy. However, studies show that a Cherokee's fuel economy is lower during winter months, especially in areas where temperatures hover at or fall below 30 degrees.

  • Park in an enclosed space like a garage.
  • Combine trips (as suggested in Step 4).
  • Avoid excessive idling after a cold start. Your vehicle will warm up more quickly if it is actually driven, versus idling. Of course, drive carefully on a cold motor. One added benefit, your heater will turn on more quickly the warmer your engine is.
  • Keep tires properly inflated (see Step 3) and use the right grade motor oil (see Step 4).
Figure 4. Your Cherokee will get worse fuel economy during the winter than it will during the summer.

Step 6 – Improve fuel economy in hot weather

Avoid reducing your fuel economy during the summer months by keeping these tips in mind:

  • Limit the use of your AC, and keep windows rolled up. Obviously you should be comfortable when you drive, but running the AC on very hot days can decrease your fuel economy by as much as 15 percent. Some Cherokee owners report using the AC when they're on highways and simply driving with the windows rolled down when they're in the city.
  • Roll down the windows when you get in your Cherokee to go somewhere, and drive with your windows rolled down for a few minutes before turning on your AC. This will help decrease the hot air inside your vehicle, which means the AC has to work less in order to keep the cabin cool.
  • Park in shady areas, and use a sunshade.
  • Limit idling (see Step 2).
Figure 5. Parking your Cherokee in the shade during the summer can help improve your fuel economy.

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