My 1999 Chevy Malibu 2.4L has 176K the engine
idles very rough as if was going die out, and the engine makes
a screeching noise, I took off the belt and the noise was still
present the same screeching noice and the engine seems
as if it was running on 3 cylinders..

I checked for codes there is no codes..
in my scanner the rpm was between 700RPM and 800RPM

Whats wrong with my car????

 

Squeak or squealing noise from the lower front of the engine is usually a worn crankshaft damper (harmonic balancer, if you will). Check for cracks in the elastic material between the hub and outer ring of the damper.

 

I took off the Harmonic balancer, I didn't find cracks, elastic material
the pulley is made of steel not plastic, I took off
the timing cover I found the Timing chain was loose
thats why my engine would shake and screech almost as if the engine
was going to die out
Im going too buy a Timing kit, water pump

 

Thanks for the update. Keeping my fingers crossed that you caught it in time.