4afc cranks but doesnt start.

[pro-16t]

I was driving when i noticed the tacho had a mind of its own & spiked to 2000rpm and back again with no change of revs which i thought was electrical.
I kept driving then the car & it died pulled over car cranks fine but doesnt start checked fuel pump have fuel checked the dizzy pulled the cap off looked inside put back on, car started strange. Drove the thing home on the way died again! Checked spark NO SPARK leads are good plugs are good, changed the coil still no start.
I'm thinking its the dizzy any thoughts people? cheers

[Jonny Rochester]

Ignitor fault, which I think is in the dizzy.