ok so i am looking at this new 94 civic cx hatch and when the guy pulled up the idle was alittle bad and i asked and he said well its missing half the exhaust but you might want to check the vacume lines. so then i go to drive the car and it only does it once but then i noticed it was when i pressed in on the brake then if i let it out it did it again so i did it fast and it kept doing it any ideas?

 

any ideas?