vader3234

1998 civic coupe manual transmission.
Speed sensor. Your thoughts?
Tach works, speedometer works very sporadically when cold but if I'm on a long freeway drive speedometer will work for the duration of that drive and then revert to the needle just jumping from 0 to 100. Cruise control works just fine when speedometer is working or not.
Cluster or sensor?

civic402lx

Check both for loose connection.

TomCat39

The other possibility is the board on the back of the speedometer has gone bad. My 5th gen (92-95) acted very much like yours and it was the speedo board.

Relic1

this says that your sensor/pickup in the trans is working.

either the speedo in the cluster is going bad (as stated) or the screws that connect the cluster housing to the speedo circuitry are loose.
I've seen both, they both act this way.
If you can solder, you can likely repair the speedo board.

CandyRedRC46

Thank you both. My 92 hatch does this too. I haven't dug into it yet, so this is a good starting point for me.

mk378

If the odometer keeps working when the speedometer isn't, the sensor should be good. Also if the speedometer ever reads other than zero when the car is not moving, that is almost certainly the speedometer head itself.