On recent days my 4Runner has been acting strange with very rough idle.

yesterday after looking around the 3vz, i found that a vacuum hose is hanging around clipped to a broken piece of tube below the power steering pump. theres 2 hoses together, one of them seems to have broken off...

Will this cause the rough idle? is this hose connected to the pw pump?

 

Got pix?
I'm not sure (more experienced hands need to get at this one for ya), but I'd say YEAH, offhand. But I'd think you'd have steering troubles, maybe? I guess if it was the return, maybe not....mine's 22RE, so it doesn't have the same layout - I only have 2 hoses.

At any rate, a hanging hose needs to be reconnected to where it belongs! Vacuum leaks CAN cause odd idle behavior etc. Did you trace out where it goes to?

 

There are two hoses that come off the back of the power steering pump, and they are vacuum hoses. Yes, this would be your problem.
See FSM download below to get the manual, then look at "Steering" "Power Steering" page SR-47 for a picture of the vacuum connector.

 

That valve opens on hard steering (high pressure from the pump) to leak a little more air into the intake, and raise the idle. So you won't kill the engine when you're trying to parallel park.

I would expect a broken hose to just raise the idle, but it's easy to check. Just put your thumb over the broken end (closing it off). If that clears up your idle, you've found your problem.

 

Will check tomorrow, thanks to all for your advice.

93toyrunner2, the ttora repair manuals are AWESOME!

 

Yesterday I got a chance to look under the PSteering pump, one of the small tubes entering the air control valve attached under the pump has broken off. Its really hard to get there, i'm guessing the pump will have to be removed to change that valve? It looks like a difficult job.

The rough idle has gotten worse, now the engine has started to fluctuate between 200 and 800 rpms constantly but it will drive fine, if i accelarate it will go for a while... Anyone seen this before?

 

Remove the battery, and the battery tray, and then you will be able to disconnect the remaining hose, and use a wrench to disconnect the vacuum valve from the back of the pump.