[Saz]

Hey wondering if anyone can help I have a Ford Focus, I have had to change the engine due to burning oil. New engine has been placed in and the car starts, however it seems to be making a popping noise intake and out. Can anyone tell me what this could be please

[olduser]

I assume you are fitting a scrap yard engine.

My first thought would be to take the plugs out, with ignition off, turn the engine by hand and by putting a thumb over each spark plug hole in turn, check for compression on each cylinder (firing order 1-3-4-2)

Have you replaced the cam belt and idler (and maybe water pump)?
If so, are sure timing is correct, did you check the camshaft actuators?

Wrong wiring should show on diagnostic tool, and ignition faults.

These are just general steps in the dark - due to very little information.

[NMNeil]

As Olduser said we need more details. The Focus has been made since 1998 and over it's lifespan had many different engine options; both petrol and diesel.