Sounds like a 1930’s tractor?

Morning all. We have a 2004 vivaro 1.9 diesel. When driving the electrical fault lights up on the dash and the van loses power. It also seems to sound like a old tractor at the same time.
I fitted a new Egr and filters yesterday, checked for water in the fuel filter and did the usual stuff but I’m still losing power and sound like a massey Ferguson.
Any ideas?