Thanks to everyone who replied! I *may* have found the problem... I hope.
I would have liked to thank you all individually, but I'm on a foreign
server and also need to resume the return trip within the hour. 

It may just have been the CHT sensor. A plastic sleeve protects the
connection to the harness, so I couldn't really see whether the connection
was good. However, when pushing the two ends together, there was
reasonable friction/resistance, which lead me to believe that the
connection was made. Apparently, this was only the frction of the
connectors' ends with the sleeve. Another reason why this was so elusive,
is that I coudln't believe that the non-functionality of a non-essential
component such as the CHT sensor could really paralyse the whole damn
thing; I assumed that a default "limp" mode would have kicked in under
this circumstance. 

There was another problem, too. While wiggling the wires, I accidentally
disconnected the vacuum assist to the brakes. Luckily I remembered a post
quite some time ago on this very problem, for otherwise I would never have
guessed this. (The diconnection was in FRONT of the firewall and could not
be seen from the engine compartment.)

Thanks again for all the help. I'll be back in a couple of days (fingers
crossed).

-- 
Sami ('75 Westf.)
dakhlia@wuecona.wustl.edu
http://wuecon.wustl.edu/~samid/