Just wanted to make sure people don't think starting their car now and then during the winter and letting it idle for one or two minutes is a good idea.


Still there's one car here that doesn't want to idle at all.

The time signal fault might just be a symptom, not the reason. When the engine speed drops far below idle speed some ECUs produce such faults.
Although changing the sensors hasn't been a bad idea. Broken insulation is a major issue.

Again check the most obvious things.

Fueling ok? The fuel pump might have stopped working or the fuel pressure might be too low. Does the pump run when you turn the key? Are the connectors (also on the pump relay) ok? Do you have fuel coming out of the injectors when you try to start the car? A fuel pressure check could also help. And even if the pump is running, how old is your fuel filter? A blocked fuel filter also might cause the problems you describe.
Spark ok? Do you have a spark on every plug when you try to start the car?

Sensors ok? You need engine speed and engine load for the ignition timing. When the MAP is shot, the ECU might think you're already on high/full load. And with the wrong ignition advance the car won't run properly.
TPS also might be worth a check. When the ECU thinks throttle is already open at idle speed it will add some fuel which will cause the engine to run far too rich when the throttle is still closed.
I'm not sure about the sensors used on the Cosworth, but in most cars (early CVH/OHC/Zetec EFIs wer different) you can check these with a simple multimeter.