Hyundai Accent 98 problem

Who can help me? I have a problem with my 1998 Hyundai Accent. The car has a vibration, and it's more noticeable when I turn on the air conditioning. What could be the problem, or is it a part that needs replacing?
For example, the speedometer doesn't hold steady when I turn on the air conditioning; it starts to shake. When the air conditioning is off, I still feel it, but less, like the car is about to stall. Otherwise, the car is good as long as I take care of it.

Oh, and another thing: could you tell me why the car loses power when the air conditioning is on? Is that normal, or is there something wrong with it, or is it related to what I mentioned above?

Thanks

, key_sting

It's normal for it to lose power, because when the compressor is working, it takes power away from the engine. And the fact that it almost stalls at idle is definitely due to the ignition coil; it sends current to the spark plugs, and if it's not receiving enough current... Although you lose nothing by cleaning the idle air control valve.

Hi, I advise you to check the spark plug wires, spark plugs, and idle air control valve (IAC). The IAC valve is responsible for increasing the engine speed when loads are applied, such as the air conditioning compressor and alternator. It does this by forcing more air into the intake manifold. Clean it!

First of all, check the alternator's charge and then the rest of the components.

If it shuts off because of the alternator, I'd have to jump-start it, right?