i have a 1998 civic EX that wont pass california smog in idle it has 176 Hc's max is 100 i have a dc header and a no name exhaust .the funny part is that it has 49 Hc's in 2500 rpm's.no trouble codes no other problems .any one can guide me in the right direction .another thing i put the stock intake air box .thank's in advance

 

do you still have a catalytic converter?

 

yes i do

 

is there a chance that cat is bad i replaced the o2 sensor 1 year ago because it gave me a p0133 code low signal .I been told by my buddies to change the oil maybe thats it .i have been driving king of hard last changed 2 weeks ago

 

Cats dont usually go bad... its probably your o2 sensor. Unless you've been messing with the cat.