I plugged in auto scann and it read "catalyst system efficiency below threshold " Im guessing i need a new catalytic converter but my cas running fine no loss inpower no over heating should i replace or leave it alone

 

Replace it or get a test pipe if it is bothering you...they are kind of expensive to replace though unless you go with an aftermarket one which will most likely fall apart inside and start making an annoying rattle.

 

fuck cat converters i always chop mine off and run straight pipe

 

He is OBD2 so putting in a test pipe will still throw the code. Check the wiring to the O2 sensor behind the catalytic converter. You could then replace that one as it is only good for 10 years and "HOPE" it is the sensor and not the cat.
Or convert to OBD1 with a jumper harness..
But I bet this would work also....Universal o2 simulator single output [unv-o2sim1] - $40.00 : O2 Simulator, E-commerce

 

I didn't even think about him being obd2...wouldn't a defouler also work if he ran a test pipe?

 

Flatrex you are right, a defouler should work and I don't see any problem with it because it is the secondary sensor.