I would like to know what size of fuel injection hose should I use to replace the small hose that goes into the fuel pressure regulator, thanks.

 

The small hose on the front of it? That's a vac hose...nothing special about it.

 

Nope sorry I meant the large hose behind the fuel pressure regulator. I tried two different size hoses and one is too big and the other too small. I don't know what size they are so don't know which in between size to get.