Got a bit of a random problem on my 2003 1.6 8v Astra. After driving it for around 20mins, I go to stop at a junction or pull up at traffic lights and when I go to pull away the speedo won't start working till I do over 20mph. I took it back to the dealers and that plugged the laptop on and they couldn't find any faults. Then it was ok till today. I went to Swindon this morning and on the way home I was coming down the M4 doing 60mph and the speedo just went to 0 and then worked again. When I got back into town I pulled up at a mini roundabout and the engine just cut out. It started again ok, then I pulled up about 10miles later and the engine cut out again so I went to start it and it just would not stay running. I had to keep it at 1500rpm then it was fine all the way home. Any help or info would great. Thanks for looking.