When I start up my car it makes a loud squeaky sound but is not coming from the belt area and lack of power?

I change the pulley I change the alternator I change the water pump I change the power steering pump the noise is coming from behind the motor underneath the car. The noise coming from behind the motor, and I change the only probably the belt tensioner the belt water pump PowerStar pump and alternator and it’s still making this squeaking noise and lack of power.