Speedometer Went Out

I'am crusing today and noticed the needle for the speedo was bouncing up and down eraticly. So next thing you know it dies and falls to zero. It used to wiggle slightly for the last two months and then just died today. The tach still works and since i can read the speed from that i can drive like this for awhile. If i tap the glass the speedo will jump from 0-10mph then go back down. What could cause this and is it expensive to fix. By the way the coolant thing has been resolved it was a hose that came out thanks.

The odometer doesn't work ethier

The odometer wont work without the speedo working.

What year is the car?

It's a 1991 3000GT SL.

Your car has a speedo cable.

It could be an issue with the cable itself, or on the cluster where the cable plugs in.

Your car has a speedo cable.

It could be an issue with the cable itself, or on the cluster where the cable plugs in.

Where's the speedo cables, sorry new to these cars

pull out the bezel and check all the leads out of the back

It's on the transmission. The other end of the cable that is, it's most likely it came out from there...that happened on mine a while back...you'll see it, it's the only cable goign to the trans if I remember correct...there is a wire that's attached to a large nut...don't mess with that, that's the reverse switch for the backup lights....the cable will be accesses from under the car so it's in a totally different location.