I have NEVER had good gas mpg in my v6

[Arsenalslr95]

Any ideas how to diagnose what the hell is going on with my car?

2015 V6, no performance mods, oil changed regularly with what the car calls for, 87 gas, 14k miles on it.

I do have 20's with 255/35/20 in the front and 275/35/20 in the rear. The rear wheels also have 1" American Muscle spacers on them. Ive heard them sticking out a little can cause drag, therefore affecting MPG somewhat, BUT.............my car is ALWAYS in the 12mpg range when I look at the average fuel economy on the dash. I do not drive in sport mode, I do not use the paddle shifters. I drive the car to and from work daily in city, with an occasional hwy cruise somwhere on the weekend. I do sit in it with it running on idle while on my lunch break for about 20 min daily. Could that be the culprit? Seems weird to me, as I did this exact same route to and from work everyday, sat in the car with it on idle the same every day, etc with my Hemi charger on 24" rims and got 13-14mpg

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[SBLee29]

Same here. I've always gotten 14-15 mpg on the stock setup. I just stopped caring after awhile. I did notice that idling brings the mpg's down pretty quick tho. I do a lot of city driving (stop and go), I'd imagine if I drove in an area with less lights and stop signs my mpg would be where it should be.

 

[fordguys550]

Sitting idling will kill it..and.sounds like its mostly toen driving. Also...depending on the time of year..ie...summer.time with ac on...i dont advize sitting and letting it idle..underhood temps get crazy high...i do this with rentals on work trips....i killer 2 ac compressors in 2 s550 v6 mustangs...the underhood heat gets so high, youll start to damage things. In the winter is probably fine though. I would say thats where most of your mpg is going. The wheels sticking out more isnt really going to hurt. I have 10" wide wheels, and 285s on all 4. I get 32mpg on the frwy. Around town i get 18 to 20

 

[markbento]

mine was around 25 using 87 when I started using 93 it jumped to 27 and with tune its up to 30 even got 32.5 on a road trip with it

 

[BosMus]

I've got a stock 2016 V6 automatic, filled with 87 octane. Before I started commuting I would average 18mpg between city and highway. Pure high way in summer I would get 26.5 mpg. Now that I'm commuting in heavy city traffic (30mins to go 4.5 miles), I get around 14-15mpg. I would recommend checking your mpg the old fashion way as well to confirm your dash info is correct.

 

[mu5tang2016]

I got about 7K on mine. I drive about 80% highway. I took delivery of the car June 26 2016. so i did that in 3 months. I use 87. I don't put it in to sport mode unless I want to beat on it. And my trip 2 is solid at 24.8mpg and that is from day 1, I've never reset it.

I drive alot of highway. I range from 28-32mpg if I reset it at 75mph and drive 150 miles. if i reset it from my driveway to highway to destination I get 26-27MPG. I don't sit idle in the car to much. only mod is K&N drop in, xpipe and GT mufflers.

One think i have noticed with the auto is it'll dog, if your doing say 45mph(in 6th) and want to speed up to 55mph slowly you get absolute shit MPG, down shift and excel faster, better. it doesn't produce shit for HP around 1600-1800 rpm and causes the MPG to be horrible, it wants to be in the 2000-2400rpm range so it's got enough power to actually move the car.

But either way i'm getting just around 380 miles per tank vs... my 14-18mpg jeep.

 

[Artem]

I'd cry if i get 12mpg on V6. I used to get 23-26mpg 50/50 driving when I had V6. Now on GT I get 21-22.5mpg 50/50 driving.

 

[Arsenalslr95]

Yea I dont know whats going on. Even if I was doing nothing but constant stop and go, like NYC kind of stop and go, this car should be getting more than 12MPG

Even though I do 80% city driving, I still travel on roads that allow me to go a few minutes without having to come to a stop. Its not like its red light to red light every 300 yards

 

[Arsenalslr95]

Duplicate post

 

[plc268]

City driving is what kills it. Idling doesn't help either.

 

[Arsenalslr95]

I mean, im sure this car had to have been designed to get better MPG in every day normal driving conditions then what I am getting, especially since everybody else that drives city states they get way better numbers. Ill try no idling next week and see if things improve

 

[soldier989]

100% city driving, 14 miles to and from work all on back roads. I average 20-22mpg. I dont use AC often, even on hot days. I throw it in neutral and coast up to lights as often as possible. I do have some fun running gears out when the opportunity arises.

Do you have a lot of uphill driving?

 

[Fuse]

I get 13mpg pure city driving. But I'm around 17-19mpg with mixed city and highway. I don't know how people get such high numbers. During rush hour 1.5 miles can take as long as 45min or longer to get through.

 

[DANA44]

I get 25 mpg mixed. I prefer to be in gear so as I am above 2500 rpm. If I am on the highway and keep it in 6th I can get over 30. Top down and a spare tire in the trunk wife in the other seat.

 

[Chris@Lethal]

Try checking your spark plugs maybe. I had a cracked plug and I was getting AWFUL MPG. Changed out all the plugs and gapped to around .32 and back to getting 30 mpg on the highway.

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