The tacho stopping is a good clue, these are classic symptoms of a failing crank sensor. They tend to be ok when the engine is cold, then fail as it heats up. This will put on the fault light too.
Normally I moan on about people who, even though the diagnostics light is on, keep changing parts without at least getting the codes read.
With these symptoms though, if it was my car I'd just fit a new crank sensor. It's an easy DIY job, but buy a proper one from Vauxhall. Cheap ebay type sensors just aren't good enough, plus there are a few different types of sensor depending on engine number. Vauxhall should be able to get the right one!
If you would rather get it plugged into a diagnostics machine first, be aware that a lot of generic code readers will not work on Vx diesels. Back street plug-monkeys will tell you there are no codes stored but it's just their rubbish diagnostic equipment.
spenser, August 2009
