I been searching the site for a couple hours and can't find anything that would tell me what this part is.
I have a 1996 4.3 vortec vin w blazer and was trying to find out what this part is. It is located on the underside by the rear drivers side fender by the bumper. It looks like a canister that sits in its own compartment with two marked fuel lines going to it. Does anyone know what this is? I can post a picture but it got to late tonight and started to rain while I was investigating under the vehicle.
Thanks

 

that would be youe evap cannister.

 

Thanks Mike
That what I was thinking from my research. I just need a confirmation I guess.

 

Yep, EVAP canister. This question gets asked A LOT.