Theres a strange noise coming from my 99 millenia's motor but seems when i accelerate it the noise goes away but wen idle the cars just clack clack clack even when driving it makes the noise unless you are accelerating like flooring it , its not the motor oil..dad changed it what can it be? please help

It sounds like you have a valve or rocker issue, I would run an engine cleaner through the engine. I suggest draining 1 quart of oil, pour in the cleaner and run engine for 5 min. Let engine cool and drain the oil. Pretty much another oil change. This will hopefully clean a sticking valve if this is the issue. But I also would check for anything hitting the pulley's or fans that may have came loose. I've seen this a lot. Good Luck. It may take 2 cleanings for the engine, so don't get disappointed.