Honda Accord 98 Problem with Racer

I'm facing a real problem with my car, it's Honda Accord 98, and the problem is when i turn it on and it's still cold the RPM goes down reach to the Zero and the goes up to the 1 and still doing this till the car became hot, and sometimes even if it hot when i stop on the traffic it makes the same problem, and sometimes when i'm turning to the right or left and the RPM reacheds to Zero it turns off!!!! this is a real problem for me and i took it to alot of mechanics and nobody knows the problem...
so please help me solving this problem if anyone faces that before...
by the way my car is a manual transmission...

Waiting for your answers