What's Considered "City Driving?" I get 12mpg

Power/Fuel
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1

Hello. So, I rotate through 2 vehicles. One is a 2008 Nissan Quest with 65,000 miles and the other is a 2010 VW Jetta with 38,000 miles.

4 years ago I moved into a new house with a new job only a mile away. I often only drive to work and shopping for months at a time. This means I usually only go through 1 tank of gas each month. I drive very gently. I do not speed. I do not rapidly accelerate. I do not brake harshly. Most months, I don’t exceed 45mph.

Both vehicles only get around 12 mpg. When I do take them on the interstate to visit family 2 hours away, both vehicles deliver their proper highway fuel economy. The Jetta will show up to 35 mpg. The Quest will show up to 29 mpg.

So, is my city driving not “city driving?” I spend no time in traffic so it’s not like I’m idling away. Both vehicles are low mileage with proper maintenance. The a/c is always on as it is hot as hell down here.

Maybe it’s normal for vehicles that basically just “go around the corner” every day. I don’t know.

2

Considering you go for a very short distance per drive-cycle, it looks to be normal.

I drive a hybrid, which easily gets 40+ MPG in city driving if I go for 10+ miles.
My company moved to another office next to my house, 3 miles drive, my MPG dropped to 25-30 max.

Until you get engine to warm up, it consumes substantially more fuel.

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Super short hops like that are very severe service. The engine doesn’t warm up, the exhaust doesn’t reach temp, the computers are running open loop and running richer than it does on longer trips. That is not city driving, it is much more severe. Follow the operators manual instructions for severe service, likely recommending much more frequent oil changes even though you are accumulating almost no mileage.

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12 mpg is pretty good for your type of driving. Google Epa city driving test to see what kind of driving they consider city driving.

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Agree. Turn on you MPG calculator to instantaneous and see what it shows as you drive. I would guess lots of times it’ll be under 10 with a few burst of 30 or so. You can do the same thing and re-set the calculator and see how long it takes for the average to come up after a few low readings.

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Yes, it is normal, since the engine never actually warms-up.
And, for that same reason, your oil change schedule should be done on the basis of elapsed time, rather than on the basis of odometer mileage.

IMHO, you should be changing the oil every 4-6 months.

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I would also take it out once a week for a half hour freeway drive to heat up the oil and charge the battery.

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Yes you are getting normal miles per gallon .

But now I am curious ( nosy ? ) what happened about the Altima you posted about and is the Mustang convertible yours ?

Do you work in a shop or just buy and sell vehicles on the side ?

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I"ve had this recommended to me before. A buddy calls it an “Italian Tuneup.”

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I manage two used car dealerships and have my own detail shop. So, the Altima is still sitting, I happened to have this guy come by who said he was a certified Nissan tech at a local dealership. He recommended getting a new ECU. I got it and it didn’t change a thing. He said he’d have to program it, but ghosted me and I’ve never heard from him since.
We do know that the girl did hook up a new battery backwards.
And if you’re wondering, she never left bad reviews for us so I guess that’s a positive.

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Similar, but that’s when you take it out and flog it, foot to the floor, to clear out the combustion chambers, etc., This is more just to get the oil heated up enough to boil out water and gasoline, and to charge up the battery.

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As the manager of 2 used vehicle lots I would have thought you would have a working relationship with 2 or 3 actual shops .

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Is that some kind of back-handed remark? You seem pleasant.
We have our own mechanics. They aren’t certified techs who know everything about every vehicle. Thanks.

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Even no stop and go driving the vehicle is still probably in a lower gear as opposed to overdrive gear on the highway. That alone will lower gas mileage.

15

As far as the original question, the EPA has a precise routing/test pad/road they use to determine mileage. It’s out there somewhere but I’m too tired to look it up.

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You would think that at least one of the mechanics at one of these vehicle lots could have answered the miles per gallon question.

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The EPA doesn’t test a one or two mile circuit. I have a trip mileage meter on all the time. It’s under 10 mpg for a mile or so, then it steadily rises as time progresses. Drive a mile or so and park as the OP does, and it’s in open loop as mentioned above by @TwinTurbo.

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Just saying the EPA has a specific testing procedure to determine the city and highway ratings with the disclaimer that your results may be different.

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My 2017 Tucson takes about a minute to go into closed loop.
About the time it takes to get to the end of my city block.
I’ve checked with an OBD scanner.

With COVID, most of my driving is a weekly trip to a grocery store 1 mile away.
The dash display mileage going there is 11-14 mpg, depending on outside temp.
The return trip raises the figure 2-3 mpg since the engine is warmer.
Even with those abysmal #s it takes me 2 months to use a half tank of gas.

Last weekend I went on a 780 mile round trip and mpg was 30-33 mpg.