Air in water coming out of sink

Hello everyone.
Newbie here. So if I posted this in the wrong spot please just let me know.
An ways I have a Viking popup with an electric water pump. I had my dealer winterize it last winter and I opened it up for the first time this summer. Everything looked good at first glance.
I filled the holding tank and drained it to rinse it out. I then filled it again and wanted to run water through the pump. I turned it on the pump runs and water comes out but so does a lot of air. Then eventually the pump continues to run very softly like it never fully builds up the pressure. If I fill the tank until it spits out and then turn the pump on it works good for about a gallon or so then starts to spit and sputter with a ton of air in the lines. Any suggestions? I really don't want to bring it to the dealer if there is a simple fix or something im missing like a way to bleed the system of the air. I'm pretty handy and want to learn more about this system but this is my first camper so please bear with me.
Thanks for any ideas provided.