Rough idle after cleaning intake manifold

[WesleySnipez]

Yesterday I removed and cleaned the top part of my intake manifold (left the bottom hold on the car) I started it when I had finished and it idled pretty rough, but drove fine. I checked the hoses again and I found that the hose going from the rear canister to this plate on the back of the intake mani was put where the hose at the end of the fuel rail goes. I switched the hose and plugged the right hose to the fuel rail,thinking it would fix it but once I started it it still had a really rough idle bouncing for 900rpm down to almost 0. What is going on????

[WesleySnipez]

There is also very low fuel pressure. It had pressure before I took off the intake and then after, there was barely any