Thanks for replying. The gauge previously did reach that orange/red boundary but now goes way beyond. Interesting, also too that when I get the jerking motion there is no engine check light staying on, it just blinks sometimes.
I have just bought an OBD2 reader in the hope this will give me more info, and I hope (but I've no idea) that it will include some Saab specific codes to point me in the right direction.
My garage isn't a Saab specialist, just a generic, albeit good, garage. The other issue is that I live in Germany, and my German isn't fantastic! Saab here are absolutely extortionate - they wanted 1400 euros, plus tax at 20 per cent, just for one xenon headlight!
So, is there any point in checking the turbo actuator? All the mechanic did was to put some silicon-type stuff around the top pipe, as he was able to pull it in and out easily, and he said it should be a snug fit. As I say, after that I am able to get far more umph, but I'm starting to think this will damage the engine. Lovely car, but both a blessing and a curse!