My Eurovan loses power before reaching 1000 rpm, but it then recovers. It does not exceed 3000 rpm either. These failures appeared after an oil change. I work in an area of uphill and downhill roads.

After changing the filters and oil, my van (diesel engine) has started having power failures. When scanning the vehicle, the mechanic told me it was the electric resistance, but I investigated a little bit more and I believe it might be the EGR that is failing: What do you think about it?