Sounds like they are guessing. Time for a new shop.
Start with checking for vacuum leaks, codes and compression. Start with basics
January, 6, 2013 AT 4:54 PM
I've had a check for vacuum leaks and it came back fine the garage are telling me it has a code showing for the lambda value but I may need a new catalyst could it just be the lambda value and how likely is it to be the catalyst as I get the feeling they are trying to get me to have a new one before the lambda value
January, 6, 2013 AT 4:58 PM
The o2 sensor code is from the missfiring cylinders. It is trying to adjust fuel mixture. It will go away once the missfires are corrected.
As far as the cat converter, a back pressure test will confirm it being bad
January, 6, 2013 AT 5:27 PM
Could you please shine any light one my problem i've already frone a lot of money at it and I maybe about to frow a lot more at it and I don't have much conference in the garages any more
January, 6, 2013 AT 5:30 PM
Without me seeing and touching it with my own tools, I can only give you my opinions based on my expierence.
Look for another shop. You need one with a jag as most systems you need a good tech to diag for you.