Is this supposed to be capped off? When I put my thumb over it, the engine starts to make a weird humming noise. When I take my thumb off afterwards the engine tries to stall.

Here are a few pictures of what I'm talking about.

Should be capped or a line should be going to it.

So... Should I look for a stray line in my engine bay?

yeah....look for a loose hose somewhere

i had one fall off when i went over a speed bump and the truck just stalled and died in the parking lot....

So according to this google picture it looks like it's capped off


But when I put my thumb over it, it just hums really loud and sounds bad... I'm kinda lost

Probably time for a new IAC valve. That's what it is.

Ohh... Alright then. So should I just leave it until I get a new one or what?

I would still try to find what goes in there.

Well in the picture I found on google I posted it looks like a cap, but when I put a cap on it, it just whines like a ****

The whining is probably because it tries to work properly but it can.

So... I should still replace it though? I don't know if I should cap it for now or leave it uncapped

I would. All the air going into the engine from that hole is dirty.

Oh, I just read a thread on cleaning it. I think I'm going to do that temproarily until next paycheck.

There is no line that goes to it. It's a port that's supposed to be vented to atmosphere.

I've never seen one just open like that. The ones that have it also have a black protector like is shown in your other photo.

I'd look for the cap. It may have fallen down on top of your intake or something. Otherwise I'd stick a vacuum hose on it, and run it towards the rear of the engine, leaving that end open. This wil prevent dirt, grime, and water from getting into the valve. (same thing is done on differentials)

Rich

My ranger sounded like a deisel and was loosing power, i had to replace master air flow sensor and wash out the K&N air filter, and a fuel filter.