Honda Repair: rough idling/loud vibrating when a/c or heat turned on, accord lx, idle control valve

Question
hello-i am looking into buying a 2003 accord lx-car seems in excellent shape except at a light the idle will go up and vibrate loudly-or do that when a/c is turned on. will idle /vibrate also even when not turned on at a stoplight. any suggestions?? should i not buy it for fear of something horribly wrong? it stops and then goes back and forth stopping and starting.

Answer
it isnt horribly bad. sounds like an idle control valve. could be because water got in there from condensation, or maybe a gasket or hose leak. im guessing if you took it to a shop they would charge you between $100-$500 to fix the problem just because it is a newer vehicle. i guess decide if you would want to spend up to that amount to get rid of the noise.

when you turn on your AC or Heat, it sucks power from the motor to run the blower, that is why the difference in idle. if the car is vibrating a whole lot, it is becuase the car is idling too low and the motor is shaking in its mounts. although you said the idle goes up when you turn on the ac so it could very possibly be another problem.