10.5 MPG !

[Enitalp]

Hi,

ok i know we don't drive a mustang for its fuel economy, i don't care.

2005 Auto, 4.10, 16000 miles old ;p

My Mustang is my Daily, in weekday i took it to go to work.

Usually i was at 20/21 mpg in town. Then one day i changed to an offroad pro chamber (no cats), and my car went to 10/11 mpg.
Then i changed for a LTH still no cats, still 10/11 mpg.
Added a supershaker, still 10/11 mpg.

If i drive my car on a long road at 30 mph. i get 25 mpg. at 60 mph on highway, i get 21 mpg. But if i drive it from 0 to 30 mph, i get 10/11 mph.
M main concern. At idle my car smell gas like crazy, if i stay near my car, got some tears in my eyes. The gas fume is insane.

And yes i need to fill up my car every 160 miles when i do only town.
My AFR is 15.4-11.0 when driving in town.

This car did had tune from 3 different tuner and the problem is still here (Bama/JDM/AM)

So my main concern is the insane smell (one day one cop will arrest me !) and my exhaust are so black ! it even removed the chrome from one of my exhaust !

What's wrong with my car ?

 

[05yellowgt]

Has the tune/tunes you have run been for an off road mid pipe? Sounds like your car is thinking that the cats aren't hot enough and is dumping extra fuel trying to heat them up and causing you to run pig rich. A proper tune should fix the problem completely.

 

[b00stedgt]

I get around 12 city with my blower cams lts and 4.10s

 

[fdjizm]

I got an updated tune for my o/r and the fuel economy went up a bit, still not better than with cats but now the ECM knows not to dump fuel to cool the cats that don't exist.

 

[05yellowgt]

My mileage went UP when I put on longtubes and an o/r midpipe. If it's not tune related then you have:

1) an exhaust leak causing the O2 sensors to read incorrectly and adding fuel trying to compensate

2) damaged O2 sensor or wiring as a result of the exhaust install.

 

[94tbird]

i get 12 city and 12 highway. doesnt matter what speed i drive 55, 75, 90, or WOT, i get 12mpg lol

 

[05yellowgt]

Hell even with e85 I get 10-12 city and 17-18 highway.

 

[SteveP]

I get 10 on a good day around the city

 

[Shaffe]

I got 4.5MPG......that was going down the 1/4 mile hahaha.

i would check your o2 sensors like others have suggested

 

[VTXFrank]

I got an updated tune for my o/r and the fuel economy went up a bit, still not better than with cats but now the ECM knows not to dump fuel to cool the cats that don't exist.

This happened to me as well. I HAD to get a tune for going with the O/R X-Pipe even though I had tons of people telling me that you didn't need to update a tune for it. As soon as I did, the mileage got better, the smell wasn't as intense and my low end power was MUCH better.

With no cats, you are ALWAYS going to be able to smell your exhaust much more than with cats. Just the nature of the beast. If you ever get pulled over, you should turn the car off regardless. It helps the officer to feel more at ease with you. But also stops them from having probable cause to check your exhaust setup. In Florida, the cops will leave you alone even if you have a loud exhaust. But the second they smell it, they want to get their mirror out. And Florida has NO, ZERO emissions testing. But they do have Federal laws about Cats.

 

[UltraKla$$ic]

Mine gets 12 gallons to the mile.....LOL

 

[waketek516]

I usually average 10-13 in the city & 20-22 highway.

O/R-X, 4.10s, and a BBR Tune.

 

[05bluestang]

Check the O2's I get about 14-16 in the city and 17-21 Hyw (Blower@9psi, OR X, Tillman (CR) Dyno Tune, 3.73's)
You are going to smell some gas because you have no cats, but not like you described......................

 

[Vapour Trails]

Put the cats back on. Problem solved.

 

[05yellowgt]

Put the cats back on. Problem solved.

Why suggest something like that? It is easily proven that removing the cats doesn't affect mileage negatively. Something else is wrong and will continue to be wrong even if the cats were replaced.

 

[SilentScope]

1) tune is not compensating for the catless system.
2) 02 sensors are damages - replacing them is relatively cheap and easy.
3) exhaust system is leaking.

I see 11-13 in city, and about 19-21 on the highway.

stock headers, off road x, GTB mufflers, 6psi.

 

[Newman]

I get 12-14 in the city and 19-22 hwy.. Intake tune 4.10's lt's and o/r X .

You pay to play .........

 

[whtcanbrwnd04u]

I get about 15-16 city, 20-23 highway.
LTs,o/r h,intake,4.10s

 

[VTXFrank]

There's barely any power to be gained.....

Uh, what? I hope you aren't referring to the 2011+ GT's. If you are, you really need to figure out what going to an O/R X-Pipe really gains you.

 

[stkjock]

tune - you need one