2011 Jeep GC V8 with low MPG compared to others
 

2011 Grand Cherokee V8 isn't getting anywhere near the average mileage on Fuelly. I am averaging 11.6 MPG. Any ideas? Is it the cold, how I drive or should I check something mechanical?

How long are your typical journeys?

What sort of driving do you do? (City, highway)

What is the temperature in your part of the world?

Holy smokes! 11 MPG?! Is that a typo?

Carrying passengers or extra cargo can definitely worsen your MPG.

Idling your engine without driving is the worst thing.

Pump the fuel type required for your engine, nothing more.

Slow down, coast A LOT more often, slipstream big vehicles when you can and don't lug things around you can leave at home. You should look up hypermiling, it is a technique commonly used to get better MPG then posted dealership figures. After hypermiling a V6 GTI that should be getting 25mpg according to volkswagen. I got 38.

Is your Jeep a V8 or V6?

AWD or switchable?

Where do you live?

Hypermiling isn't something everyone is willing to do all the time, but understanding it will help your driving. But the fact is these Jeeps don't get great mileage.

I suggest a trip to test your high MPG out; travel far enough to burn one tank of gas pretty much non-stop. This will give you a clear indication of your high mileage mark.

My experience with the large Chrysler V8s (4.7 and 5.9L) is that you mileage is directly related to how much stop and go you driving you have. These guys suck gass when accelerating. If you're getting that MPG on the Hwy something isn't right, but if you're in town 10 to 12 sounds about right. In one spread out town of 50000 where there is no real downtown and the stops are spread out every 5 or 10 city blocks I can get 13-14 MPG. In a town of 200000 where the stops are every block I get 10 MPG. On the highway I get 20 MPG at 55 MPH and about 17 at 70 MPH. This is with a 4.7L 5 speed. The 5.9L can do better on the highway with the cylinder deactivation if you keep your speed down closer to 55 MPH than 70. If you're towing much of anything then your mileage is probably about right as well. BTW both of these motors prefer extra octane. They run better on 89 and will yield slightly higher mileage on it (especially when towing) but the gain isn't enough to justify the added cost.

Thanks for all of your responses. I haven't towed anything and don't carry much. Usually it's just me in the vehicle. It is a V8 AWD so I knew the fuel efficiency wouldn't be good but I needed something to tow in the summer.

MMUK - I live in West Michigan and it's been in the 20's and low 30's lately.

MatrixDom - It has been running while parked a fair amount. I didn't think it would make that much difference but I will stop that and see how much things improve.

wr - My driving is almost all in the city with start and stops all the time.

I don't drive very far to work so my mileage isn't going to hurt my finances that much but I still want to be as efficient as possible. It sounds like I am getting close to what I should be getting. I will look up some hypermiling techniques and see if they help.

Never idle for any length of time when you do not have to. You are just wasting gas by getting 0 MPG while idling.

I think the MPG you are getting is to be expected under the circumstances. Short trips (=engine still cold), stop/go driving, 4-wheel drive, ...

It should improve a bit when you stop idling it, and also improve a bit when it gets warmer (as long as you don't use A/C).

Also make sure your tires are well inflated. Even a little higher than the door tags say is good for fuel economy. If the door says 32 psi put at least 5 psi over that to get better fuel economy. In winter you may lose 5 psi becuase of the low temps. Don't warm it more than a minute in winter. Drive away slow on cold mornings and drive live Ms. Daisy's in back for the first mile. Engine will warm up faster that way. Consider lighter weight oil in the winter if you are truly cold for long periods os time. The owners manual will give you the cold weather oil options.(Less friction). Also, if you have a manual shift mode, use it to upshift as soon as you hit 1,500 or 2,000 rpms every time. Getting to the highest gear keeps rpms down and MPG up. Good luck! Hopefully it will break -in too and increase becuase of that. Winter is always the low MPG season, more air resistance, low tires, snow, winter fuel blends, thicker oil....etc.

According to EPA your vehicle is expected to get 13MPG for city driving. https://www.fueleconomy.gov/feg/Find....s&id=30209

So at 11.6 you really aren't that far off. The additional 1.4 MPG that you're losing could easily be the idling and cold temps. But you shouldn't expect much better.

I replaced the air filter, stopped running the car in the driveway or parking lot and am taking longer to speed up. I will have to see how things go but they seem to be improving. The warmer weather will probably help as well.

Thanks for your suggestions. I appreciate it.

Hi,

I am purchasing a Gauge that reads the data from any vehicles computer. All recent vehicles have an On Board Diagnostic port. ((OBD II) required by the EPA)This will allow me to see my instant MPG, (and many other things. The one I am buying is a little over 60 Bucks. (Ultra-Gauge). They seem to only sell over the web, It's worth a look.

Knowledge is power, I need to adjust the nut behind the wheel!