Replaced egr valve. Still rough idle from cold

Hi.

Can someone please help. Im tearing my hair out.
Have a Renualt Grand Scenic. 1.9dci. 120000 miles. 2004.

Only purchased 2 weeks ago.
Test drive fine, drove home ok.
Next day started car and felt like it was running on 3 cylinders. After a while it was ok.
Dash showing Check injectors, check emissions.
Sometimes the Check injectors goes off but the check emissions is always on.

Kept doing the same thing. Sometimes even rough idle when warm.

Called green flag. The checked and said that only fault showing was a egr fault. When they cleared the error it comes back.

All injectors are ok, tested glow plugs. One faulty so I changed it.

This week I also replaced the egr valve.
Still the same.

What on earth is wrong please?

Can anyone help???????????

Thanks.

Kevin

Replaced egr valve. Still rough idle from cold