Mitsubishi Repair: problem on my rpm timing,was throttle body?, air cond, throttle body

Question
problem on my rpm timing,was throttle body?
mine 4g93 rpm timing , without air-cond was stated around 1k rpm, no problem and unshaking at all.
but when i switch on my air-cond, rpm timing drop to 200-300 and whole engine, steering shaking seriously.
can i ask why my timing suddenly drop seriously after i switch on my air cond? was it throttle body problems or others ?

thank you. from keng.

Answer
Keng: when you turn on the ac it pulls more power from the engine so it pulls down the engine. I would check the belt that runs the ac to make sure it is in good working order, see if the compressor for the ac is in good working order. But also when is the last time you did a good tune up on your car's engine, sometimes the engine will pull down because it needs a tune up. Does the car heat at all, loosing any water? Those could be a sign of a weak water pump and if that was going bad it too would pull down the engine when you kicked in the ac because it would have to work harder. So there are some things to check. I don't think the timing is the problem if the car runs ok, till you turn on the ac. Hope this helps and God bless: Linda