230F 1991 shaky motor

does anybody know this phenomena?
The motor was shaking and vibrating heavily just after it was started. The
whole care was shaking. I have opened the bonnet to watch the motor. It was
shaking just as it was running on 3 feet...
I opened the trottle and the shaking stopped. I went for a smooth ride and
couldn't detect anything wrong. The motor was spinning like a kitten.
what has happened?

 

Like you said; it probably ran on 3 feet...
Have you checked the plugs and the cables?
Was it very cold?
The petrol-filter might be dirty?

Gert

 

I have seen this twice on B2xx engines, both times I think it was an
intermittent head gasket leak. The logevity of the Engines combined with
lack of corrosion inhibitor in the coolant can cause an intermittent channel
between cylinder and cooling system.

Water gradually leaks in under certain conditions (temp / standing time) and
then seals up when the engine starts, the plug is wet and won't spark until
it dries a little.

If you leave it too long it can form a larger leak which intermittently
dumps the entire coolant into the cylinder under the induction stroke and
the engine will overheat very quickly.

I would advise that I am guessing a little, and am in the process of doing
this on my 940 Turbo, although it also had other problems, it did have this
symptom. The fix is a head skim and new head gasket.

 

The fuel window is very narrow. Buildup in the throttle body keeps the
throttle from closing compleatly causing the TPS switch to send an off idle
signal to the ECU. Clean the throttle body with carb cleaner and a rag and
it should resolve the problem.