Rough acceleration until about 35-40mph

Hi, can you please advice.
I own 2002 Chevy Impala 3.4L engine, 111,000.00 miles.
My car doesn't accelerate well until about 40 mph, especially when it is going up the hill or from the start in general (it works fine downhill). I have to really press the gas pedal and then when it goes over the 40 mph it works ok.

Check engine light indicates EGR valve, so I put a brand new valve and it still does the same thing.

In the process I discover that when driving without EGR valve connected to the computer my car works fine but it won’t go faster than about 65-70mph. After 70 mph when I press the gas pedal it actually decelerates and engine starts heating.

At idle engine works fine but when trying to accelerate you can hear really fast RPMs but it just doesn't deliver power to the wheels?

It also produces roaring noise even if I press the gas pedal to the max, doesn't react to the until it passes 30-40 mph.

Please help, Max A.