[AnthonyG]

I would really appreciate any help anyone can provide.

A week ago I bought a used Nissan Micra 2003 (new shape) as a private sale. A day after owning I was having an issue where on turning it on the engine would cut out after about 20 seconds.

You could bypass this if you revved the accelerator pedal. And the car would then go and be fine.

Obviously this was not good enough so took it to a garage to be repaired (a good garage and highly recommended one).

They replaced the O2 sensor on the car as this was the fault showing but it didn't fix the issue so they have been exploring the problem now. They could not find anything wrong of 5hrs of looking at everything.

The garage owner suspects it may be the ECU at fault which was £250 plus starting price with labour ontop. The car is not worth all that amount (I paid £700 for it just one week ago).

So its a case of taking the car home. However now the car will not work as before. It cuts out after about 2-4 seconds of turning the key.

It just seems to lose power after about 4 seconds and then cuts out. So its not the immobiliser.

If it is the ECU is there any tricks or workarounds I can do to just get the car home. Is there anything I can try myself. As I have bought a lemon here in this car and have no comebacks as it was a private sale.

Or do people think there is anything else than the ECU possibly causing this.

[Hometune]

So sit in the car with the windows closed. Turn the key to ignition on and listen. Can you hear the fuel pump running - a quiet hum from under the back seat? If you can then the ECU is switching the pump on and you know the pump works.
Next step is a compression test. These engines, particularly the early ones, have timing chain stretch problems. You need to ascertain that the valve timing is correct as the injector signal from the camshaft signal must match the crankshaft signal. This is where I would be looking first.