Very black smock with black powder, poor acceleration, AC on Car RPM drop down sudden and car stops

My ford fiesta is in trouble. Fallen down the speed and not getting power as I accelerate.

and black smoke and black powder . Usually when pressing hard on accelerator and starting time.

I have checked on computer it was giving MAF sensor error but when I check MAF it was giving good readings. Now mechanic told me that we should change MAF but I am not sure about it that it will work good enough after changing MAF.

My car has driven 1, 03,000 Km.

What should I do?

my car was once overheated but I noticed and stopped at that time. And after that I clear that issue soon.

Is overheating nearly @ 120 Celsius for lil time.. !

Car is starting and working. But no power. Mean no turbo pick up. And black smock / and black powder comes from exhaust when I press hard on accelerator.

EGR pipe inspected with too much carbon. And I cleaned. Then no error of EGR for while.

After sometime again EGR problem seen. Should I clean it or replace it?

MAF sensor changed but still poor acceleration.

Turbo checked and its working fine as ford technician said.

No other engine voice as technician said.

please help!