Is there any reason why the rev counter would misreport the actual engine rpm?
Presumably it takes it's feed from the crank position sensor; and if that were lying the engine wouldn't run...
Gauge goes off the scale long before the rpm's stop.
Does the omega support live data on OBD as I can't get the thing to work with my Elm scanner?
The rev counter needle is driven by a stepper motor from the crank position sensor, and if accelerating hard might not keep up with the signal, or stop moving quick enough. Or, the gauge is damaged in some way, loose needle perhaps? None of the gauges are intended to be precision instruments, they are a representation of what is happening. The rev-limiter is an integral part of the ecu and can be trusted.
3.0l are not OBD compliant. You need more specialised equipment to read them.