So I'm going to be changing my fuel filter in the next day or two because my blazer ('99 4dr 4wd) is sputtering and stalling and it seems to be a fuel problem. I'm hoping it's not the fuel pump but am prepared for it. While checking out my tank and straps to see if my tank can easily be dropped to replace the pump and sending unit (way easier taking the bed of my truck) I noticed this black "box" like object mounted up under the rear bumper end on my driver side with fuel lines running to and from it. I didn't really see where they went because I was tired of laying in the snow but I'm not sure what it is? When I did the pump and sending unit on my '90 K3500 7.4L I didn't run into anything that looked like this. Could it be an emissions thing or something in newer vehicles. It almost looks like it could be an external fuel pump? I'm not sure and idk if I should budget for replacing it if it comes down to the pump being bad, or scrap it or blow it up? Any ideas?

 

EVAP canister

What is that box thing?

 

beat me ^