I cleaned the MAF and try to relearn the idle by disconnecting the battery. I already check the intake pipe up to the throttle body but I can find any sign of leak.

The engine is not knocking when cold. But after few minutes of driving every time I needed to stop I also need to put the gear in Neutral cause it knocks so bad. Sometime engine dies.

 

Check the IAC and try cleaning the throttle body. It's probably gunked up.

 

Do I need to replace the IAC gasket if I remove it from the throttle body?

 

Generally no. Unless you nick it or it is broken. Then again, if I were in a pinch and it broke, I'd just use some quality Permatex RTV sealent and carefully make my own gasket.

 

Done cleaning it, I can still hear it idle up and down but now it's not visible looking at the tachometer. I only hear it even the A/C is off.