Ive also had an Omega 2.2 a few years ago that we fitted a cam sensor to which we bought from a Vauxhall specialist. that one caused us problems. ( with old sensor fitted, it logged cam sensor fault, with new sensor fitted it logged lots of sensor faults )

We found that the sensor was non genuine, So we then replaced it with a genuine sensor which cured the problem.

Last week, we got a phone call from a local garage and they had exactly the same problem after buying a sensor from the local motorspares shop. ( so either the sensors are faulty or incorrect application for the 2.2 omega ) as they are different to the 1.8 and 2.0 litre but look similar.

We Sell and fit lots of sensors and use both genuine and non genuine, but you just have to be selective and if problems occur, stop using that particular sensor.

One Particular sensor we used to use lots of is the Corsa C X10/12 XE We Use Facet sensors and have paid as little as £9.00 + vat for them in bulk and must have bought a few 100 over the past few years. I can remember having 1 possible faulty sensor in all that time returned from a regular customer, so it was never Tested or refitted, For the sake of £9.00 it went straight in the bin. ( faulty or not ). Even Genuine Parts fail on occasions and make you waste time checking it out as you know that the part is new and genuine so cannot possibly be faulty.

I would try to steer clear of intermotor but on occasions, if it was all that was available, I would use it if it got the car up and running again. ( When the dealers are 5 times as expensive and on back order etc ) If I was wary about the component, I would inform the Customer what part I had fitted and Why.