Idle problem

[cwass99@rogers.com (cwass99@rogers.com)]

Hi,
     I was running through the Bentley tests as part of the ongoing effort to
deal with the Little Beastie's rather erratic idle, and I made a discovery that
I don't understand.  I disconnected and plugged things, as per Bentley to set
the idle, and it idled really nice.  Best it's been in a long time.  I noticed
when I hooked everything back up, the idle went to shit again.
     Further tests revealed that if I pinch off the hose going from the intake
manifold to the valve cover, the idle smoothes out.  When I set the idle, I put
a block in the end, so I doubt that length of hose is leaking.  I even added 
clamps where there were none before to make sure the joints weren't leaking. 
No good, still idles badly.
     I guess I should mention it's an 87 8v.  Also, found a part Bentley
doesn't mention existing on my car.  It's a big black Jetronic part, 321 906
263 B (for those who have Etka), looks a lot like a knock box.  Except, I don't
have a knock sensor and there's no vacuum line into the box that I expected. 
Any idea what this is?  I hate having things in there I can't identify ;)


-- 
Cheers,
Colin

If you can read this line, you're probably not illiterate.