Cold start device for fuel injection

[Panic Button]

I know how a choke works on a carburettor.

What sort of cold start mechanism is there for a petrol injection car?

I have a P reg Astra, and often I have a moment of loss of power or stalling. Only once per journey, and the warmer the weather, the earlier it happens. To me this suggests the switching off of some sort of cold start device.

My tame none franchised Vauxhall garage suggests it is a faulty 'stepper motor', but in Haynes this is desribed as an idle speed control motor. That description suggests it only affects idling, but my problem happens when driving.

[Big Bri]

the choke works with a coolant temp sensor usually located on inlet manifold . try cleaning out the throttle body first with brake

[Big Bri]

cleaner ,sorry about that