Can anyone help me out here? I changed my cat (I already had a new one), but they changed it anyway... And now it actually did worse! The HC and NOx was in the failing region (as opposed to before) it was on the NOx. I'm about to go back and have a high flow cat put on, they say thats better so I will do that... Any suggestions?? Thanx

The motor is a 94 gsr 60,xxx on bottom end and about 1000 on head since rebuild
It has new valves
New valves seals and guides
ITR Dual valve springs
ITR cams (Could it be the ITR cams??)

Should I change my O2 sensor? (it used to run rich, maybe that messed it up)
I already changed spark plugs, should I get some better ones?? Should I change oil?
WTF can be the problem? Plz help, I've just about had it with this car... :wtc: