I had some time and some nice weatehr to investigate my little problem. I
checked four plugs - all in fine condition, all gapped the same within spec.
There is one suspicious spark plug boot - the red rubber ring around the
socket appears to be largely gone. Gave all the sockets a bit of dielectric
grease just to be kind. did the same at the distributor.

I checked all of the electrical connectors at the injectors and dabbed a bit
of dielectric grease for good measure. All electrical connectors within the
plug look shiny.

So, what is the device that plugs int o the intake air boot and has an
electrical connector attached? My Bentley does not identifiy it. I has a
sort of half-round copper tube with a 3mm hole pointing into the boot.
Whatever it is, it was full of oily crud. Scraped that all out, almost got
it shiny inside. It is next to the hose that goes to the idle stabilizer
control valve.

I examined the throttle housing and looked for signs of wear at the
butterfly gate. All is well. The only free play I could find is with the
gate open.

Anyway, I take it for a drive and the condition described in my initial post
only reproduced once and not as dramatically as previously. After the engine
got hot, I had no problem.

Funny things:

   1. I noticed that my in-gear-idle speed is lower now by about 150 rpm.
   I also did not get as much of the idle sticking at 1500 rpm when I come to a
   stop. What did I do by cleaning the above mentioned intake air boot sensor?
   2. My Bentley shows a hose from a charcoal canister to the top of the
   air filer housing. I have no such thing. What does this mean?

--
mordo
1990 Carat