Hello,
I used to get 180 miles to the tank when I had cats. Since removing them and adding Dynatech cones, I now get about 115-120 miles to the tank.

Thanks,

Tim

 

I think your foot got heavier with the extra HP

 

I wouldn't imagine it would make that big a difference. I think razor has it pinned.

 

I agree with razor, and your getting awful gas mileage if you got a 15 gallon tank.

 

ease up on the gas lead foot.
you should be at least 19mpg = 285 miles

 

Get it tuned... When I had my headers installed it ran rich.

 

ya 115 is horrible!!!! You got o2 simms?

 

that is flat out ridiculous gas mileage. even 190 to a tank is like 12 mpg. Do you floor it all the time lol?

For real, you have other issues, you have to be running rich, check your O2s, and indeed headers can cause your car to run rich if it has not been tuned for it.

 

maybe getting a locking gas cap will get that 180 figure back

 

get some new o2's and get it tuned.

 

yeah with my setup I get around 200 miles a tank in the city with a pretty heavy foot too, and got almost 350 all highway miles moving pretty quick. maybe some bad o2's like every has said or maybe leaky injectors???

 

You didnt get O2 sims for the front O2 sensors I hope.

 

I got 10mpg once because my car kept trying to go into closed loop, but I didn't have the VSS hooked, so it couldn't. It stumbled and bumbled all the way down the highway. Is the car running alright?

 

Damn I just did a MPG check and with two races and not takin it easy at all on the throttle I still got 17-18mpg!

 

Hey,
Something must be wrong with the car then. I did have the car tuned when I did the H/C swap. I do have the front O2 sensors, but had the rear ones deleted out. I haven't had new O2's in quite some time. I've been getting a miss at random at 5k rpm off and on lately.Other than that the car has been running fine. Since the original PCM tune, I added a ported intake and a Walbro 255 fuel pump, msd 6A, 4:10s, EWP, new opti---that's all
In all honesty, I thought the car was getting good gas mph at 180 per tank. I did get a little more when I had the 3.73 gears though. For a few days since I deleted the cats, I have been keeping my foot in the gas showing my buddies the difference in the sound and overall loudness of the car. I knew the car drinks gas when you get on it, but D@%^, this is ridiculus.

-Tim