So Im trying to find vacuum leaks and I traced two vac lines back to this gray canister on the passenger side of the engine compartment. What is it? Ive posted two picks for you to look at. Its from my 91 4.0L AW4 242 with ABS. Really curious to know what the heck it is and what it does. Two vac lines run from my intake manifold to this gray canister.

 

i think that is the emissions canister

 

Looks like the Evap. system canister. It stores fuel vapors from the tank until the engine is started, then runs them through the engine.
Dan

 

do you check the black tank behind the front right of the bumper

 

Yup, looks like the fuel evap (charcoal) canister.

 

thanks for the help everyone! and yes ive checked the black canister thingy(lol) that line is still good... for now