They can be routed so the wiring is too close to the exhaust manifold which degrades it, best cable tied well away.

Only other problem is what they are attached to.....the rest of an omega

They tend to be troublesome, reasons why are probably debatable. Are you saying you think you might have a faulty one ?

i know i have a faulty one this will be my 4th one in 2 years and there all genuine gm ones, its been to the dealers for a diagnostic and there saying it needs some diagnostic tests at an extra cost of £340 quid which im not willing to pay, as there saying its something else causing the sensor to become faulty.

If you decide you need diagnostics avoid the dealers and go to someone on here who has Tech2. I would think that MarkDTM would be your nearest (Nottingham). He has probably forgotten more than most dealers fitters will ever know.