Before that, there's no indications.

When I started the car, the malfunction indication light was on and then flashing, the engine's rev was unstable, sometime the engine wanted to stall, few minutes later, the engine stablized as normal but the malfunction indication light still on, I have driven for serveral feets then there was a strange sound that looks like something has broken. but the car still running and there is some metal knocking noice from the back of the car. no fluids leaking.

Anyone knows what the problem is? Thanks very much!

 

wow........

First things first, like everyone else will say: Hook up a computer and get the codes and see what you are dealing with.

Then someone can be in a better position to help

 

im going to guess P0300 and any combination of (P0301 P0302 P0303 and P0304) among others. but thats a shot in the dark because YOU GAVE NO INFORMATION ABOUT THE CAR IN QUESTION.