Truck is 1994 Ranger with 2.3 liter. One of the hoses comes from exhaust manifold but doesn't connect to anything. Bought the truck like this and it runs fine, but should I be worried about carbon monoxide poisoning or something? What are these hoses supposed to connect to?

 

Hose in the first photo....looks like the previous owner detached the intake hose and put an aftermarket filter on it. You can see where the square flange meets up with the original air filter box. You would be much better off removing the aftermarket filter, install a new proper filter in the air filter box, and re-attaching the intake hose/flange to the box. The factory filter box draws cooler air from the outside, while the after market filter installed just hangs there and draws hot air from inside the engine compartment.
Just take the 2 screws he used to attach the flange to the filter setup he made, and re attach it to the filter box.
Second hose is an "air preheater hose" It links up from the exhaust manifold to the air intake tube. Its sole purpose is to allow warmer air to the intake system on cold/very cold days during initial startup.
Not really necessary until real cold weather sets in.

 

Some one has converted it over to a HOT AIR intake instead of the factory cold air intake, not a good change

In your first picture you are holding the air plenum tube that pulls in air to the engine
The metal piece with the 4 holes should be bolted to the Factory air cleaner box(on the left), and the cone filter end should be removed, and.............discarded is the most pleasant way to put it, lol

As for the second picture, that flex tube is for a pre-heater used mostly in colder climates, its not "exhaust", the thin metal pieces its attached to form an air chamber around the exhaust manifold where the air can be heated quickly after cold start of the engine
There was a Cold Air intake tube that came out of the lower end of factory air filter box and ran forward to a hole in the rad support, this pulled in cold air from behind the grill for better engine performance
That tube has been removed, previous owner was a kid or an idiot, there is no other option, lol

That flex tube would have been attached to the Cold Air tube with a valve that opened and pulled in pre-heated air for the first 4 or 5 minutes after cold temp start up, to get heater working faster and engine warmed up faster
This also lowered emissions on cold starts so was required in some areas

The pre-heater valve was run by vacuum hose from top of air filter box, where there is a thermal switch/valve(no power needed) it had 2 vacuum hoses, they may be gone or just not connected

You would definitely be better off with a working factory system, more power, but without that lower Cold Air intake tube what you have now is what you are stuck with

 

Thanks for the answers. I was just about to put in a new, correct air filter for the air filter box and noticed a couple more things that should be connected to it but aren't. Here are the pics. At the top of the box there appears to be something electronic not plugged in. At the bottom as I am pointing out, looks like something is supposed to go there. How important are those things?

 

In the top picture you are pointing at the Cold Air Intake there should be a hard plastic tube on that and it runs forward to a round hole in the rad support

The air pre-heater flex tube would be attached to the above cold air intake via a vacuum activated valve, activated by........read below


The bottom picture is the bi-metal thermal valve, not electrical, those are vacuum hoses, one vacuum line to the engine, other would go to the pre-heated air valve on cold air intake tube
When the bi-metal valve is cold it opens, so on cold starts the engine would pull in air that's warmed up by exhaust manifold warming up, as the bi-metal valve gets warmer it closes and engine gets cold air from in front of rad support

 

Thanks for the answers. So, with the correct filter put in the air filter box, would I be able to re-connect the plenum without any problems? I wonder why someone would disconnect the plenum from the air filter box and put on an aftermarket filter?

 

As said because it was a kid or an idiot
Maybe they thought the Ranger was TOO FAST so they changed the air intake to slow it down a bit

Yes, you can hook it back up to factory air box as is
It would be better with the cold air tube running to hole in rad support but it would be better than you have now with the smaller cone filter, you can probably hear that filter when you REV engine now
Anytime you can hear air being pulled into an engine it means there is turbulence, that's the noise, and that's a BAD thing

Also that hole in bottom of air box is a "mouse house" entrance just waiting for a new tenant