as of lately my gsr has been running strange and sucking up a lot of gas. im doing an oil change next week, and replacing a valve cover gasket. theres a check engine light and i had it checked out and its that i need a new cat... but i dont think that should affect the mpg that much on it but i could be wrong.. any suggestions on what i should check and or replace?

 

If ure O2 sensor is bad. It will cause ure cat to go out from running to rich and give you bad gas millege.

 

^^^ x2

 

your cat could be clogged, feel exhaust coming out of muffler with your hand, do a general tune up if needed, especially fuel filter.

 

I'm having the same problem with a 2001 GSR. Getting about 250mi/tank. Should be easily over 300.

 

if the cat is to be clogged how can u clean it out or is it just better to replace because theyre not too cheap i know that much or is it something you can do out of your garage