XJ Cherokee MPG: Real-World Numbers

Nobody buys an XJ for the fuel economy. But nobody should be surprised by the numbers either. Here's what to actually expect from the two most common XJ engines, the 4.0L inline-six and the 2.5L four-cylinder, along with the variables that push those numbers up or down.

The 4.0L Inline-Six (Most Common)

The 4.0L HO (High Output) engine that powered the majority of XJs from 1991 to 2001 is rated at 190 hp and 225 lb-ft of torque. In a stock, well-maintained XJ with 4WD:

• City: 14–16 mpg
• Highway: 18–21 mpg
• Mixed: 15–18 mpg

These numbers assume: stock tire size (215/85R15 or 225/75R15), stock ride height, properly tuned engine (fresh plugs, clean injectors, working O2 sensors), and no roof rack load. Real-world mixed driving typically lands most 4.0L owners in the 16–17 mpg range.

The 2.5L Four-Cylinder

The 2.5L four-cylinder XJ, available primarily in the earlier years and in the two-door Sport trim, gets slightly better economy on paper but often disappoints in practice because the engine works harder to move the same weight.

• City: 16–18 mpg
• Highway: 20–23 mpg
• Mixed: 17–20 mpg

The four-cylinder works well for commuter use and light-duty trips, but it gets worked harder in hilly terrain, on the highway at speed, or with any load in the vehicle. Many owners have found the MPG advantage over the 4.0L to be smaller than expected.

What Kills MPG

Several common XJ modifications and maintenance conditions significantly drag down fuel economy:

Bigger Tires

This is the biggest one. Going from a stock 215/85R15 (roughly 29 inches) to a 31-inch tire typically costs 1–2 mpg. Going to 33s costs 2–4 mpg. Every inch of additional tire diameter increases rolling resistance and rotational mass, and the stock gearing wasn't designed for it.

Re-gearing the axles when going to larger tires partially restores economy (and driveability). Most owners who run 33s and regear to 4.10 or 4.56 report getting close to stock MPG numbers back.

Lift and Aerodynamics

A lifted XJ has more aerodynamic drag, especially at highway speeds. A 4-inch lift with a steel bumper and roof rack can realistically cost 1–3 mpg at highway speeds compared to a stock, smooth-bodied example.

Maintenance Deficiency

Fouled spark plugs, a lazy O2 sensor, a clogged fuel injector, or a stuck-open thermostat all hurt economy measurably. An XJ running at 14 mpg when it should be at 17 is often one tune-up away from improvement. Fresh plugs, a new air filter, and a thermostat check should be your first moves if your numbers seem low.

4WD Engaged on Pavement

Driving in 4Hi on dry pavement isn't just hard on the drivetrain, it hurts economy too. Make sure you're running 2WD on dry roads.

Realistic Ways to Improve MPG

• Fresh tune-up: Plugs, wires (if applicable), air filter, fuel filter, the basics. This is the first step before any other optimization.
• Properly inflated tires: XJ tires should typically be 30–35 PSI depending on tire spec. Under-inflation increases rolling resistance noticeably.
• Check the thermostat: A stuck-open thermostat keeps the engine from reaching operating temperature efficiently. Cheap to replace, notable impact on economy.
• Clean injectors: A professional injector cleaning or a quality fuel system cleaner in the tank can help, particularly on higher-mileage engines.
• Regear if you've lifted: This is the biggest single improvement for lifted XJs. Match your gearing to your tire size.
• Reduce drag: Remove the roof rack when you don't need it. Aerodynamic drag at highway speeds is more impactful than most owners realize.

Bottom Line

A stock, well-maintained 4.0L XJ in mixed driving should consistently hit 16–18 mpg. If yours isn't, start with a full tune-up and check the thermostat. If you've lifted and run bigger tires, adjust your expectations accordingly, and consider a regear if the economy penalty is bugging you.

You're not buying an XJ to save on gas. But there's no reason to accept worse numbers than the truck is capable of delivering.