i took my car to my dad's mechanic today; ive been getting my "Servic Engine Soon" light on for a while...he hooked up that computer type thing into it [???] and got the code

"P0420 CAT Effic Below Threshold (BNK 1)"

and then he just cleared the code for now, and i drove about 40 miles after it was cleared, and no light; now if the light comes back on, should i take my FrankenCar intake out b4 i take it to dealers? and is it possible that the intake is causing the problem?
thanks guys
atw

 

I'm not sure what that error message means, but if "Effic" stand for "Efficiency", then you may have a problem with either your front pre-cat or an O2 sensor. I can't imagine what effect the Frankencar would have on that. But you might want to reinstall your stock airbox before you go to your dealer just to be on the safe side.