Going to check over an rs500 tomorrow that is cutting out at around 4K. Goes dead apparently. Bit like a rev limiter??

First thought is phase sensor, poss even ECU??

Loose wires around distributor maybe at certain revs... or even engine management wires??

Could the crank sensor do this even?

Map sensor would be another port of call.

Any other ideas welcome - as will be doing a bit of head scratching I reckon???