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Poor MPG

6K views 25 replies 15 participants last post by  ktmdude 
#1 ·
Hi,
I am a new owner and I've gone through a few tanks of fuel and have noticed I am getting a little worse gas mileage than what many people have reported on the site. Combined I am only getting 21 to 22 MPGs. We do a pretty good mix of city and highway driving. My typical daily commute is only about 7 miles round-trip and that is all city going almost entirely uphill on the way to work and downhill on the way home. My wife's commute is more like 30 miles round trip about 75% on the highway, not too hilly. We tend to alternate cars each day. Living in the Salt Lake valley we are a bit hilly here but I was still hoping that I get 23 to 25 MPGs combined. That being said, I did get 29 MPG on a 290 mile trip on the freeway. I am very happy with that.
My question is given the elevation we live at (4200 ft) and some hills involved, is this the gas mileage I should expect? Is there anything maintenance wise that could be done to help clean something in the system and possibly improve the MPGs? Still better MPGs than our old SUV so I'm not really complaining just slightly disappointed.
 
#5 ·
I was getting near 30 when mine was new with the factory tires. However, with the addition of a roof rack, rock rails, and BFG All Terrain tires that has dropped to between 20-22... (My tires are a size larger than stock though, so if I did the math it may actually be a tiny amount better.)
 
#7 ·
Thanks for the responses everyone.
I do not have any aftermarket racks, parts, etc on the Jeep so that's not an issue. I do believe it is on its second set of tires (it has 36k miles at the moment) so I will look into the size, etc. Its sounding like this may be normal given my elevation and terrain.

My throttle body and EGR are still pretty clean as I live in a warm climate...
Should I, in anybody's opinion, look into cleaning of the EGR, throttle body, etc? Would that be something that could be effecting things at my current mileage?
 
#10 ·
Throttle body and EGR are fairly easy to see and clean. It all depends on your driving. My engine most of the year still is warm when using it in the morning thus it helps to reduce carbon build up vs cold climates.
Unfortunately the cleaning will be short lived but doing so will help you eliminate another variable for reduced fuel mileage.

I also changed from the Fortera's which by the way I liked and bought the same size Michelin's which was supposed to be fuel saving low rolling resistance tires. Not one change what so ever. If I had to do it all over again I would buy the Fortera's and save about 400 bucks even though I am a Michelin guy on all my vehicles.

If your tire diameter is different so will your fuel mileage. You might verify that your new tires are the same diameter...
 
#12 ·
I will check the tire size. Do you know the size of the originals? Also do know of a link to explain the throttle body and EGR cleaning? I really am big on preventive maintenance especially as I plan on keeping this car for a long time. The idea of my car going into a shop for an extended period of time and having a repair that costs thousands of dollars is sickening to me. I believe in taking care of things that I have purchased. It's also one reason I've been a little weary of buying used cars as you have no idea if the previous owner truly took care of the car. My other car was only one year old when I bought it and the Jeep is a 14 which we just bought so it's 3+ years old. Beyond that I haven't had a used car since the late 90s. With how much they cost these days, unfortunately I don't have much of an option but to buy used if I want to get the car that I want.
 
#14 ·
My 14 got 28-30, but my 16 gets 21-27 at best.
 
#16 ·
OP: As to your original question, there were a LOT of variables in there and trying to figure out what is normal MPG for you would be impossible for most of us.

Now, it's possible I'll get flamed for this but.. There is a huge difference between driving a standard 5 speed automatic gas guzzler and an 8 speed diesel automatic. If you want to get good MPG, learn to keep your foot out of the pedal, learn to take your foot off the pedal at that sweet spot RPM to let it shift to the next gear, make sure your tires are inflated, and learn some of the basics of hypermiling.

Just my advice!
 
#17 · (Edited)
I put 40K miles on a 2014 diesel and now have 43K on a 2016 diesel, so 83K combined in JGC CRDs. The OP’s numbers sound about right to me. I’m currently getting low 20s overall MPG in the 2016. I think I got better MPGs in the 2014 but I’d have to check my fuel log — I log it when I get fuel, the old fashioned way, putting pen to paper in a small notebook. Every time.

I recently did a short check and got 30 MPG highway for a 50 mile stretch, doing 65 MPH, the tranny locked in 8th, and using ACC. That 30 MPG was on the odo gauge, not hand calc’d.

The best I ever got on a full tank, hand calc’d, was 35.5 MPG — the JGC CRD went 835 miles on that tank, all highway miles. That was with the 2014. (Post #17 in http://jeepgarage.org/f222/hypermil...ange-700-800-900-miles-90121.html#post1236484, back in Oct 2015)

I have 32” tires and have not recalibrated my speedometer for the larger tires, so I am actually getting about 3% better MPGs (and going 3% faster than the speedo says). I’ll probably do the recalibration because I’ll likely stick with 32s. This is my 1st set of 32” tires. So I actually got 36.6 MPG on that run that I linked to. On A/T tires to boot, so it can do a little better.

36.6 MPG on this rig, to me, is pretty awesome.
 
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#18 ·
Last night, for 50 miles after filling my tank, I did a highway MPG run — locked in 8th gear and ACC set to 65 MPH. I got 36.7 MPG.

The dashboard display showed 35.5 MPG but since my tires are bigger it is really off by 3.359% (calculated in another JG thread, here, https://goo.gl/B5inV6). Factor in that 3.359% and it’s 36.7 MPG.

And the 3.359% delta means I was actually traveling at 67 MPH, not 65.

I tried uploading the picture of the dashboard display from my iPad but it says invalid file format for (fileName).jpeg. I’ll see if I can get it.

36.7 MPG — not bad.
 
#20 · (Edited)
We took a 4,000 mile road trip and got 27.2 MPG on mostly freeway miles and now have 73,000 miles on the odometer. I stuck to the posted speed limits which were 70-75 MPH for most of the miles although we ended up going much slower between Fort Worth and San Antonio with nearly constant heavy rain.

On a 6,000 mile trip in 2014 we got 28.3 MPG although that trip had fewer miles in city traffic.

Everything is bone stock on our Overland 4x4 with the ORA-II except the tires which are Goodyear Wranglers.
 
#22 ·
went to MI over the weekend and i average 30MPG. Before that trip or even in the past i only average 19 to 23 MPG. I drive my truck aggressive. During the weekend trip I tried to drive between 60 to 70 that were I got my 30MPG hand calculated. On my EVIC is 33.2. I would say this is all on your driving style. I always drive 75 to 80 on the highway.
 
#23 ·
Here I am a year later. We just complete a 1700 mi road trip from SLC to St. George, UT (southwest corner), then east to the North Rim of the Grand Canyon, down to Flagstaff on our way to Phoenix then to Vegas and back home to SLC. A few days city driving in St. George and Phoenix and we averaged 27 mpg. Can't really complain about that. A lot of hills and mountains going from 4200 ft to 6500 ft, down to 2800 ft, up to 8300 ft, down to 1100 ft, up to 2000 ft, back to 6500 ft and finally down to 4200 ft. She ran like a champ the whole time while being quite comfortable. Bad news is either my radiator, coolant tank or hose blew today... coolant everywhere... ��
 
#25 ·
The coolant was a false alarm. Some how the reservoir cap came loose and hot coolant blew out the top. Had the system pressure tested and did a fish and refill as it was something I wanted to do any way due to residue in the reservoir and because I had to cross contaminat the coolant to get to the dealership.
I bet your lose of mpgs is more the tires. Winter tires made a BIG difference in the mileage on our other car and it wasn’t for the better.
 
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