after i installed headers, cat, and cat back on my 2000 civic, i have had a slight rough idle. when the car is at running temp, it will idle at proper rpm but it is slightly rough . enough to notice it. the car has new plugs, wires are good, there is no cel. im fairly new to this stuff but i have read i cannot re program my ecu! how do i fix this? it also has a short ram air intake if that matters at all

 

You need a program and knowledge to retune your car. You might just want to clean the idle sensor its probably dirty

 

from what i have researched i cant re program my ecu in a 2000 civic its an obdb2

 

You might want to try a Seafoam treatment of the engine.

 

try the two things already mensioned... clean the idle sensor, and run some seafoam thru the motors vacume like directions say. that should clean it up.