once again 91 f150 5.8L 351W engine, looking in the engine compartment, the pump type of item on the bottom left that is hooked up to the belt. has what looks to be a hose fitting on top and back of it. what is this pump called? what does it do? what hooks up to it? i also see a vacuum canister and something on too of the inner passenger fender well. thank you in advance.

 

Air pump. It introduces fresh air into the engine to help combustion, canister is a reservoir to keep vacuum during low engine vacuum situations.

 

should these be hooked up? the canister has one big inlet hook up on side towards engine, and there is a top section with 2 hook ups for hoses on it. it wasnt hooked up when i bought truck so i have no idea

 

no, on some there is an opening on one side that looks like a hose connection, but the small vacuum hoses should be hooked up.

 

no non no. lol your on a different part, i know what you are talking about, it has green and red vacuum lines on it, there is another canister in front of that. right behind the battery

 

That takes in air for your smog pump. It should have a port facing the firewall with nothing connected to it, and one facing the engine with a hose that runs to the smog pump.

 

Ok the small round thing.

 

which one are you talking about? i have a small what i think is a check valve with a bracket going down to a bigger canister with one hook up going towards the engine with what seems to be a metal hose rapped in something "hugging" the fender well that seems nothing can be hooked up to it. the smog pump has one hook up on the top and one on the back of it also.

 

there is a small one on top of a big one, lol

 

...I think we're all lost?!?!?!?!?

Can you post a pic?