Gas milage; 1998 Grand Cherokee limited.
I am looking to improve my milage on my 98 grand Cherokee limited. I drive 27.5 to work daily (then another 27.5 home). On a 17 gallon tank, I get 200 miles.
I don't take it off road. I can't get the cruise control to work, which would improve things if it did work since most of my commute is out of town. Keep the tachometer under 2k except when climbing bills. I keep the fluids in good condition, just changed the transmission fluid last fall, and rebuilt the braking system aside from lines and master cylinder last month. I keep the vehicle light, just a spare, jack, and basic tools. The engine runs great, doesn't run rich or lean. I baby the thing. Any tips other than what I have done already to improve my mileage. Some have suggested adjusting the fuel/gas mix to make the engine run more efficiently. |
I this a AWD version? I never understood the Quadra Trac. If I want my Jeep in 4 wheel drive I will put it in 4 wheel drive.
When is the last time you checked or replaced the plugs? A clogged cat won't help. O2 sensors. While they might not be throwing any codes poking around on the internet will tell you they should be replaced anyway somewhere at 100 to 150K. And how accurate is your MPG estimate? Are you running bigger tires? Cause that could throw off your calculations. Also since it is winter I am wondering if you get the same mileage in the summer. People talk about getting worse gas mileage from "Winter Gas". I think it is just cause we let are vehicles warm up more but........ Also I am guessing you have an overhead console. What does that say as far as average MPG goes. I put one in my '00 XJ, did not come with one, and on longer trips the overhead console reading seems to be fairly accurate. What is not accurate, least I am pretty sure, is my Miles Till Empty read out. Also my gas gauge in the cluster is a little off. Almost positive. When I fill up, and I fill up all the way when I do, she never takes quite as much gas as I think it will from the reading on the gas gauge. About 2 gallons less then I think it will every time. Sorry for the babbling. Just all the things that popped into my head when I read your post. |
That's... quite low.
In addition to what Ralph77 said, I would strongly recommend the 4 port injector upgrade. I use Bosch 0280155703 in mine and they are a great improvement over the stock ones. Obviously part of that is the stock ones being 23 years old, but I believe there would be a not insignificant difference between them both brand new. Check cylinder compression maybe. Tire pressure good? Also, are you measuring mpg with the console, or by gas fill ups + odometer readings? The latter is much more accurate and dependable, just make sure your tires are correctly sized to get proper odometer readings. |
Originally Posted by Hatsuwr
(Post 3540531)
That's... quite low.
In addition to what Ralph77 said, I would strongly recommend the 4 port injector upgrade. I use Bosch 0280155703 in mine and they are a great improvement over the stock ones. Obviously part of that is the stock ones being 23 years old, but I believe there would be a not insignificant difference between them both brand new. Check cylinder compression maybe. Tire pressure good? Also, are you measuring mpg with the console, or by gas fill ups + odometer readings? The latter is much more accurate and dependable, just make sure your tires are correctly sized to get proper odometer readings. Butt dyno tells me she seemed peppier and idled a little more smoothly but just as Hatsuwr pointed out could just be the fact that I replaced 15 year old injectors with a 145K on them. LOL. All in all don't regret it one bit. |
Have you checked your brakes are not dragging including the parking/hand brake ?
200 miles to 17 gallons is poor - especially if you are mostly out of town. |
I get the same mileage as you to a tank and it’s mechanically sound . I’ve driven countless 4.0’s never had one that got even half decent mpg and knew that going into it . The only place i see unbelievable mpg is on forums lol |
Originally Posted by GreaseMonkey17
(Post 3540567)
I get the same mileage as you to a tank and it’s mechanically sound . I’ve driven countless 4.0’s never had one that got even half decent mpg and knew that going into it . The only place i see unbelievable mpg is on forums lol If I reset the MPG on the computer and make a longer journey of 10 miles+ I will get an average of closer to 18 mpg. On a journey of 50+ miles on a good road with free moving traffic I've had 23 mpg average. Jeep is a 2000 WJ 4.0 and has done under 82k miles. |
Originally Posted by thatguy1
(Post 3540487)
I can't get the cruise control to work, which would improve things if it did work since most of my commute is out of town.
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Originally Posted by Cherokee_Mike
(Post 3540592)
Most of my journeys are under 5 miles into town and back again and I get around 12-13 mpg.
If I reset the MPG on the computer and make a longer journey of 10 miles+ I will get an average of closer to 18 mpg. On a journey of 50+ miles on a good road with free moving traffic I've had 23 mpg average. Jeep is a 2000 WJ 4.0 and has done under 82k miles. |
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