I've noticed that i got bad gas mileage since i installed my o/R x-pipe and C&L racer CAI... I used to get 200 miles with a full tank, now i'm getting 150 or less. Do you have any clues? Maybe my O2 sensors died? Or it's probably my tune since i got to order a custom tune for that CAI...
Moreover i got new 20" rims...and it's worst! Lol

 

Maybe you are having too much fun with your new mods, getting into the throttle more?

Or maybe the new tune is rich?

And yeah the 20" wheels are probably contributing too.

 

Sounds like you weren't getting very good mileage even before the mods. I average a lot closer to 300 miles a tank in my car, with 3.73 gears...

Do you do a lot of city driving?

 

My rims has been installed 1 month ago, the bad gas mileage was already there

And my tune is probably rich , i'm willing to order custom tunes at AM but there is a problem with filling the shipping information.

I'm trying to drive safely every full tank now to see if it's not my foot, and it's not..

Yeah, i'm only city driving...i can't imagine 300 miles a tank, that would be my dream!!

 

Thats probably a big part of the problem that there's not a lot you can do about. These cars are many things, but fuel efficient around town they aren't.

See if AM can write you a tune specifically for gas mileage.

 

Not sure what the cause is, but that sounds really low to me. I've still got the factory setup, but average 300+ miles a tank, with a mix of city and highway and the city portion is 25-35mph roads. When I take a long highway trip, it gets closer to 400. I have 3.55 gears and generally run 93 octane, so not sure if the gas helps a little or not, but for me to get under 200, I'd guess i'd have to spend a lot of time sitting at traffic lights or something, as I'm not driving in a fuel conscious mode when I drive either and the highway portion has its fair share of traffic jams.

 

Yeah lots of traffic lights here and accelerations/stops a few meters long, and i forgot to mention that i got 4.10 too, but they may improve mileage in town?
I'll try to re install my sct canned tune with my cai that doesn t require a tune and see what happens.
If it' s not better , it's my x-pipe or my o2 sensors then!

The problem is my "new " fuel consumption, i think there is a problem somewhere...thanks for helping guys

And yeah we didn't buy mustangs for fuel !

 

I get over 300 per tank and I have a whipple running a 3.375 pulley for 11 lbs of boost and still have the stock 3.31 gears.
Something is really wrong in your situation.

 

Wtf... 300 miles with a supercharger mamamia

I read that if 02 sensors are faulty, they can running the engine richer.
I suppose one is bad, how can i check 02 sensor whitout installing a brand new one? Monitoring with sct and a computer?

Are front and rear sensor the same?

Thank you guys for help

 

If your o2's are bad they'll hit you hard with gas mileage. If you were going to get custom tunes anyway start with that, then see if that changes anything.

 

Yeah i'm about to order new custom tunes from AM...
I just wanna swap rear and front sensor to try (rear are disabled) i think they are same, difference is heat resistance?
I can make rear sensors heat resistant with a few things at work so this is not a problem.

 

Front O2 sensors react faster than rears. Switching may produce codes and cause engine driveability problems. Did someone mix sensors when xpipe was changed?

 

I'm gonna try this week end, and i'll post results!

 

i checked gas mileage on my speedo yesterday and it was saying 8 mpg in town and 12 mpg at 60 mph... wtf!



Today i removed front 02 sensors, when i was about to switch front and rear i noticed that they re different, front ones are larger than rear and plugs don t fit.

So this is not possible to swap front and rear 02 sensors!
And i can't check them...or i had to buy a wideband sensor to monitor.