Engine Cutting Out

So about 6 months ago I bought a 1998 Peugeot 106 1.1 petrol 3dr, when I bought the car it was running fine and I mot'd it in December, then one day I was going to the shops in it and about half a mile down the road at about 40mph in 4th gear it just cut out, so I dipped the clutch and let it out but nothing so I turned the ignition to 'off' and then turned it over and it just started again. So now it cuts out every 40 seconds on idle and 90 seconds when driving and the only way to get it to start again is to turn the ignition off completely and then start it. But, about 3 weeks ago it started to run fine again then after 2 days of running sweetly, it started cutting out again, So far I've ran fuel into the engine using a can of petrol and a separate pump (basically not using the cars fuel pump) so I know it's not the pump, I have also changed the idle sensor. Has anyone had this issue or knows a cure for it?? Thanks