I've had the Catalytic Converter Below Efficiency code (67) on for 2 weeks and it seems like my gas mileage on this last tank has gone to shit. Car seems to drive fine though. Does the car do anything to compensate for that engine code?

Defanitly will affect power and gas milage.

im picking up a magnaflow (carsound) universal high flow cat for $80. gonna have to get it installed so figure another $50 so $130 isnt too bad at all.

bad cats can do a ton of bad stuff...bad mileage, fires, etc.

My old Corrola burned a cat out & used to shut the car down in mid-drive...just going down the road...all of a sudden...putt, putt, putt...nothin...

Turns out there was a piece loose & would stop up the exhaust...

Yea, I guess I'll get the OBX hi-flow cat and have that installed, maybe throw on the OBX headers for fun also.