Yesterday my high mileage 92 LS400 starting bucking at idle, but drove fine at higher rpms. When I popped the hood, I heard a loud air "wooshing" sound. I saw the was a stub of a hose coming off the front top of the block. When I put my finger over this hose, there was considerable suction and the engine would idle normally. This hose clearly broke, I just can't figure out where it went. Can anybody help me? Thanks!

 

You're going to have to be more specific. Or better yet, take a picture.

 

^^^ ?

He has taken a picture. A pretty specific picture of the exact hose he's speaking of.

Plug the hose. Problem solved.

 

it looks like a vacuum hose for the power steering pump? check this pic out.

 

I'll check again when I get home. No picture is showing on my browser in the original post.

Just got home. Yeah that goes to the IAC valve on the power steering. Kind of weird how it just broke though.

This should help you find it: http://www.lexls.com/tutorials/steer...mpremoval.html

 

Yes, that is one of the two hoses going to the idle-up valve, or idle-air valve (not the IACV) on your PS pump. Those valves are infamously prone to failure - read up on that if you have not done so already.

On my '91, both of those hoses were extremely brittle and I ended up just replacing them with generic by-the-foot vacuum hose. I'll guess that exposure to PS fluid from the leaking valve somehow accelerates the brittling of the hoses.

Easy fix to just replace the hoses (you'll see the other one ending at the PS valve), but if you're seeing white smoke at startup and losing PS fluid, your valve may need replacing too.

Just plugging the open hose should work fine as an at least temporary fix. Doing so will prevent the idle-up valve from increasing idle air (to increase RPM) while you're steering at idle - during parking, etc. Unless your car dies while doing that, or you need some extra PS boost, plugging should be fine. You should of course track down the other end of the hose to make sure it does not find itself into a pulley or belt or something.

 

Oops, I jusr scrolled down to the picture without reading the notes up top.

 

Thanks everybody. Yeah, plugging it is working for now....I'll do my research and look for the other end of the hose when I have time and report back.