need info or help on short ram intake

Hi, Alright I have a 2000 Focus zx3 with 100k on it I had installed a bomz short ram intake. For the first month or so it was fine I had problems with the car typical bogging. Well the bogging totally stop I went to local AutoZone they checked computer everything is fine (spark plugs etc). Now when this was installed and when I hit the throttle it was a good hp gain. Now after 2mts or so im not getting the same throttle response it's like the car's hp is back to stock. Do I have to buy a diff filter or would engine need to be clean really need help on this thank you.

have someone check the o2 sensors, and cat converter for restrictions (i.e. clogged)