Audi A4 b8 2011

[bricky09]

Hi , everyone, i just purchased a new egr valve with cooler, fitted to car , started but bad knocking noise from the new valve ,so removed it again and took the cooler off it and refitted to my old valve ,car started great no noise bad as normal, but a few hours later lights on dash and car in limp mode, scanned with vcds and fault shows , 4892 egr valve (N18)
P0403 00 (036) Malfunction Intermittent not confirmed.

Any help would be great.