Universal air filter fitted instead of kn cone on discovery 1 v8 now wont idle

Merry Christmas guys, hope your day is full of great memories.
Now my question, I've got a snorkel fitted and had to remove the k&n cone filter . . I purchased a unversal air filter fitted it and it looked sweet. So I started her up and OMG it could hardly start and couldn't idle.
What have I done wrong? How can I fix this? When I took filter off and connected back to snorkel with the pipe but no filter it started sweet ut you God it drinks more fuel more than a v8 normally drinks.
Is it that I have to have it retuned? Or disconnect the battery So ecu has to do something to pick up the change in air being fed through the snorkel and filter rather than just the cone k&not filter in the engine email bay.
I'm so bloody confused , can anyone help me with this please
Dave

Hot wire afm?
Disturbed any of the electrics?
Forgotten to plug anything back in?
Any blockages in the snorkel?
If you disconnect the snorkel altogether is normal service resumed?
As it ran better with the filter removed from the snorkel I'm inclined to think there's an issue with the amount of air entering the engine & consequently the mix is very rich.
I suspect with the filter fitted to the snorkel the air flow was even more seriously restricted making the mix even richer & that is quite capable of causing rough running.

Thanks for responding ratae, with the snorkel taken out she runs sweets, nothing not connected, no blockage in snorkel. So I'm very confused. To stop the ram air effect I've turned the intake to face backwards. But it has no filter in place so thinking of getting a pre filter snorkel top.
So again I'm confused

As normal service is resumed with the snorkel disconnected the problem is the snorkel & its effect on the intake of air.
The airflow is restricted but the injectors are supplying the normal amount of fuel.

You either need to restore the airflow to what it was before or a complete rework of the ecu to reduce the pulse length of the injectors. Problem with the latter - even if it might be possible & I've no idea if it is - is if you reduce the fuel you're going to affect the performance.

What ecu/afm combination is fitted?

I take it this snorkel is a recent fitment by yourself?
Is it new and the supplier has sold it to you as suitable for your application?
And there are NO restrictions in the snorkel or any connecting tubing - even by bends in tubing?

Perhaps a few photos of the setup might help, esp for those who have snorkels fitted & might spot something odd.