crazy speedometer and lack of power

[docsavage]

My '92 740 Turbo wagon has a speedometer that has begun to jump from
zero to thirty while idling, and when driving it will drop to zero and
jump up to thirty and back.

The wagon has another ailment at the same time, when accelerating and
it feels the wagon should shift, it backs off, as if you got off the
gas, or a governor clicked in.

Whether or not these two things are related or give a clue to the
problems of each I don't know, but it they both are existing at the
same time.

Any ideas?

 

[JvC]

Have you removed the instrument cluster recently? I have seen that
behavior in my speedometer. If you remove the instrument cluster and
misconnect the wires (tachometer to speedometer), that will happen. In
my case, it also fried the speedometer. I can't speak to the shifting,
as I have a stick.

John

 

[Mr. V]

Speedometer: it is probably the sensor that picks up the RPM speed on
the differential; inspect and clean it, look for frayed wire
temporarily shorting out.

Transmission: power flush the fluid and change the filter.

 

[John Robertson]

stop spinning the wheels

 

[Roger Hunt]

stop spinning the wheels

And remove the chain attached to that lamp post.