If your engine was running great, why did you need to change it?
Or do you actually mean that you had the oil changed, and now the engine doesn’t run as good anymore?
Engines don’t need to be changed unless they are running bad.
I can’t tell if you changed the engine, or just the engine oil.
If you mean that the oil was changed, and now the engine doesn’t feel as good, then you need to take your car to a different shop, and have the oil changed to the proper oil for it.
BC.