Hi
My Leggy GT had a km/h to mph conversion before I bought it. It's fine up to Motorway speeds, but then the speedo needle goes a little 'vague' deviating between 5-15mph.
I had a flamer kit fitted and when you flick the switch, the needle goes mental! I kid you not - anything from 20mph jumps at Motorway speed, right up to off the clock, 'check engine' light and the car stalls at low speeds!

I've uprated my earths and it's not that. Any suggestions?

Cheers

 

interference from the HT side of the flamer kit??

Try some supression?

David