Hi, I have a Honda Accord 1987 LX Auto Sedan. when car runs on idle, or at traffic light the RPM goes below 400, and i have to change the gear to N till I start accelerating again. i took it to some mechanics, one said it is my fuel pump, the other one said it is my carb, and some other ideas... at this point i am confused and could someone tell me what is exact problem please? any help would be appreciated.