new here with a problem

[Melanie]

hello,

I have a Vauxhall Vectra 2.6 MSD GSI 2001.

we bought the car & the engine management light comes on, we had it put on a diagnostic scan machine. it comes up with fuel trim bank 1&2, which we have been told its a exhaust part we need or maybe a sensor. we took it to a garage & we were told that he could sort the problem so we left the car with him, when we got the car back 2 days later the engine light came back on, so I called the garage to find out why this was. then I found out that the garage had actually de-catted our car, obviously this shouldn't have been done so we never took the car back to them. so now we still have the problem with the light coming on & also now having to replace the front manifold cat converter.

I have the part but there is no guarantee this will solve the engine management light issue, after talking with a few Vauxhall mechanics they are saying that its a 60/40% that its the back cat on the car & not the front. obviously we wont know until we replace the front one first which got removed, so we definitely have to do that one, the big problem I have is if it is the back cat, where would I get the part as I have spoken to so many car parts places & even Vauxhall themselves & all I'm getting told is that they don't make that part anymore. 

if anyone at all could please help on this situation would be so much appreciated

Many Thanks

Melanie