some problems about my Honda CRV

I drived my CRV for more than 3000 kilimeters last week, then there are
some problems.

1. When I accelerate from low speed to high speed, such as from 20km/h
to 40 km/h, there is a noise under the hood, when I release the gas
pedal, the noise gone.

I take my CRV to a garage, they said that there is something wrong with
the exhaust pipe, anyone know is it the right reason?

2. When I drive, the car can not go straight, it goes a little to
right, I changed the front wheels, it still goes to right. so do I need
to do a wheel alinement? I did it 5 monthes ago.

Thanks very much.

 

A hole in the exhaust pipe would definitely cause a noise. How many
miles/years on this CRV?

It could need another alignment. All it takes is one pot hole to mess it
up. Check that the air pressure is the same in both front tires. A low
tire can also make it pull to one side.