ihave a 92 civic dx with a d16. and for some reason it idles high untill u take off it goes down..but when u stop it idles backup again??

2nd..on the in take systems were or how can i extend it out..under my filter there is a hole were mystock intake went. or can i extend or add on my pipe to stick it in there? would it make my car sound better that way or just leave the filter on it..couple of my friends were talking about running the pipe threw the hood with no filter ontherecar,but irealy dont
want to cut my hood.

 

could be the idle air control valve. pulling a check engine light? maybe the iac wire on the ecu may be loose somehow. but check that and let me know

 

Possibly air bubbles circulating, or PCV?

 

try adjusting your idle from the throttle body