Check Engine Light On problems of the 2007 Cadillac STS

This Cadillac make & model does not have an american engine, a fact that was not disclosed to me upon purchase. The engine light has came on several times in the past and dealership would mess with wires under seat and somehow get the light to go off and tell me it was the airbags that would make the sensor go off. Then when I pay my last note and get to 100,000 they decide to reveal to me that the same engine light defect means real engine problems. So after letting two more highly recommended mechanics diagnose the problem I was told by both that this was not an american engine but a very cheap german engine and that they had a large number of people having the same problem, with some having to sell their car for scrap metal. I am very upset to say the least and would never buy another Cadillac. I would like to contact other Cadillac owners that had this problem and bring a class action lawsuit.

Check engine light continues to illuminate even though I have changed both O2 sensors twice. Dealer keeps telling me I need another O2 sensor. Aldata shows a software upgrade is neede to correct the problem.