It would seem that you have an electronic speedometer, one of those 5 wires should be yellow in colour follow the yellow wire back it will either go into the ECU connector or go to the Speed Transducer which will likely be mounted on the bulkhead. Hopefully it is the latter and you can check for tightness and a good earth.
As a quick check that might be worth doing before anything else, do you have a spare coil or could you get a coil they don't cost too much replace and try that? A coil that is failing especially when it heats up can cause erratic engine performance, its a low cost item and worth a try, you just never know.
Last edited by britmog; 03/12/20 07:17 PM.
