Will a damaged Catalytic Converter affect your gas mileage?

I have a 2004 Jeep Cherokee Ltd Edition and it needs a new catalytic converter. Does that affect the gas mileage? I am planning to have it repaired this week. Will driving it in the meantime cause any damage?|||Try to get it fixed ASAP it probably won't affect gas mileage etc. but it is very bad for the environment. Driving it in the meantime will only damage the environment I don't think it will leave any damage on your car.|||I have a 1991 Toyota pickup I've driven for about 6 years. My intown driving always gave me the MFG rated of 18-19mpg. Recently I rodded out the catalytic converter, WOW, what a difference. I'm currently getting 34.1 MPG. I've also noticed I get better mileage with out ethanol in the gas.

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|||As soon as you can you need to bite the bullet and get it fixed. Once you do, you'll be glad you did. Your car WILL run so much better.





When my catalytic converter went out I couldn't drive much over 50 MPH and the car really dragged. As soon as I replaced it, we were able to drive normally again.|||Driving the vehicle until you can get it fixed should not be a problem...if you drove it for a long time it may affect your fuel mileage but you will be fine until you get it fixed...Good Luck|||No, but since other causes in effect ruined the cat, like running rich/lean due to various reasons, that does ruin MPGs.|||it does affect mileage and runnability but it won't hurt anything|||both the previous answers are correct.