I have an 91 with the I6. My evaporative system is not hooked up. I have the charcoal canister, but no lines going to the throttle body. I have no purge solenoid. The little vacuum ports on the throttle body that are supposed to be hooked up to the canister are blocked off with plastic caps. Just realized that all this stuff is missing. I guess the previous owner did away with this system. Funny thing is I'm not getting any codes. Anyway, I'm wanting to hook it back up like it's supposed to be. Where does the purge solenoid get it's power? It has to hook into a wire harness somewhere but I don't know where. Thanks

 

Found it. It is under the intake runners by the fuel rail.......for those of ya'll who care . My only question is if it's worth the $100 or so to hook the canister, purge, and vacuum lines back up and make this system functional. I'm not getting any codes for it's not being there when it should be.

 

Its purpose is to keep fumes in the tank from evaporating into the atmosphere. Having it hooked up helps the environment, but it's not going to affect how your truck runs.