vauxhall astra sxi 1.8 (2000) keeps cutting out

[toffeelady]

Hi, I bought my car in july and was made aware of it cutting out occasionally and it was explained it had done this from new.I was told by previous owner its a computer chip fault which was of no great importance to be put right.
For my own peace of mind i took it to garage, they replaced a sensor and an earth cable that was broken,since then the car cuts out almost everytime i approach a junction,traffic light and basically whenever i slow down or brake.And sometimes when breaking the car judders as if it is going to stall.
I explained to garage that it got worse after they fiddled with it and now sometimes when starting car it revs quite high , so they plugged it in to diagnostic machine and it showed nothing other than engine was 12 degrees hotter then it should be, whatever that means.
Please help as its becoming a pain.
Many thanks;-)

[tombrandy]

How many more times do you need telling? you have been given several answers already.

[toffeelady]

Yes i have been given a few answers but i was also advised to place post in motoring section.
There is no need to be rude.