shrpsh00ter

Ok guys, my 97 is horrible on fuel and I have looked everywhere for issues. I just bought it and it has a small exhaust leak, but I am getting maybe 10 miles to the gallon. I have a check engine code for O2 sensors but I chalked that to the exhaust leak. Any suggestions?

BuckB91XJ

Bad O2 sensor(s) will definitely cause you to get horrible mileage. I'd get the exhaust leak fixed, codes stripped and go from there. If your mileage is still crappy or you pop that code again get the O2 sensors replaced or prepare to be good friends with the pump.

jronald

10 is not that unusual for either engines.

Sorry
Ron

tjwalker

1. Never ignore a check engine light. Get it resolved.

2. Be sure tuneup hardware is fresh. New Champion copper plugs gapped to .035, new plug wires, distributor cap and rotor

3. Must calculate gas mileage to be accurate. Gotta do the math. Miles driven divided by gallons consumed. Get at LEAST 3 samples before making any conclusions. Trying to figure your gas mileage by how many miles you get on the odometer to a tank of gas is not very accurate

4. Oxygen sensors have a finite lifespan of between 100k and 150k, depending on the efficiency of the engine.

94JeepCherokeeMan

Last time I told somebody that, they told me that the gas gauge isn't accurate enough to do it any other way. I just know that I can get a tiny bit over a hundred miles per quarter tank of gas on the highway.

BuckB91XJ

Man! Keep on doing whatever you are doing. I remember getting 400-410 miles to a tank back when my XJ was stock. It still gets 16-18mpg on the highway even locked F&R, geared down and pushing 33s. I count myself pretty lucky getting that with my setup. I am a stickler for keeping the engine well tuned, though. I'd have to agree that 10-12mpg around town is pretty normal. The 4.0 litre isn't a stop and go type of engine. It likes to cruise at 2200-2400rpm. That's when mine does best on gas. that is doing about 70mph with my current gearing.

94JeepCherokeeMan

I get about 17 city, 21 hwy. That last trip to Moscow was 425 miles, and I pass fairly aggressively, too. Third gear up to 65-70 miles an hour, then quick shift to fourth or fifth once I pass the vehicle in front.

xj wheeler

Its really easy to figure your fuel mileage if your odometer works good. Also you have to fill the tank completely for two consecutive times and if your speedometer is not correct it will affect your calculations. Simply fill the tank, note your mileage, drive, fill tank again, note mileage and gallons taken to fill tank. Take the second mileage and subtract the first, then divide the mileage sum by the gallons and you have your mpg. Example, 180,646 mls. - 180,364 mls. = 282 mls. divided by 15.2 gallons = 18.6 mpg.

shrpsh00ter

Ok... I just went ahead and installed a whole new factory exhaust. Pipes, muffler, cat, and O2 sensors. It fixed the fuel problem but I know have a throttle problem. It is only when I am coming from a stop. When speeding up, around 10-15 mph it drops in throttle. It doesn't stall out but I just lose all throttle for a second then it kicks back in but is slow. Any suggestions?

BuckB91XJ

A hesitation on acceleration usually means you have a vacuum leak somewhere.