www.SmartCarSense.com - New mufflers- now i have horrible gas mileage?

New mufflers- now i have horrible gas mileage?

I have a new impala ss. i just bought Magnaflow mufflers for it and switched the factory ones. i can see a huge decrease in my gas mileage. what can i do to fix this and what is causing it? I am NOT constantly pressing the gas harder to hear the sound. i am smarter than to do that. even when i am on the highway, and i put the cruise on so i am not hitting the gas, it uses more than gas than usual.

Public Comments

Just replacing the mufflers isn't going to mess with your gas mileage like that. How much has the MPG gone down? EDIT: Guys, he said he only had the mufflers replaced which sit right by the trunk floor, he said nothing about O2 sensors, removing cats or any of that stuff.
Did the muffler shop mess with the oxygen sensor down by the catalytic converters? Did he remove the cats? How about replaced exhaust pipes with highly restrictive bends/kinks in them? Mufflers alone should not hurt the mileage of your car.
No Cat,No Oxygen sensors,Theirs your sign.
I don't think your new mufflers will affect your gas mileage. Try checking it again for a couple more refills. There are a lot of factors which affect your gas mileage.