i've got a 1998 honda civic ex that dosent pass smog it started just no passing by a litle max was 100 i was at 176 then i did normal tune up replaced the 02 sensor and cleaned trotle body with sea foam .also replaced timing belt ,timed it is perfect timing but now with the car hot from a 60 mile commute has 460 hc at idle and they slowly creep down to like 190's hc or less but at high idle i can get it down to like 39hcwith 12.9 co2 9.0 o2 but as soon as i decelarate it goes to like 600 then works it's way down .just dont know what else to do it has a dc sport header with carb number dont know if it's the right header for the engine cause it has the o2 sensor by the oil drain plug also i discovered that the car has a crack along the exhaust port of the resonator and also that the seal between the last flange at the muffler is also leaking can this cause my car to act up the car runs great other than that .any help i would apreciate thank's