I have fitted a new Smiths electronic speedo with a new electronic pulse cable for the reading. The speedo is fully programable so I have set the right TMP to suit the car. Its A+ engine and gearbox. Given the cable and dials are new I would expect a smooth needle going up and down regardless of speed. What I get is a jumping needle up to 15/20 mph then smooth as silk.
The new pulse cable seems to fit in the gearbox end fine and given we are working with an electronic pulse signal there's no cable that could be an issue.
The only thing I can think of is that there is something a miss with the speedo pinion inside the gearbox. Maybe the teeth have worn which could result in an unsure reading at low speeds?
Anyone got any ideas?