Cold start troubles, I daily drive mine so I need to get this sorted Options

[Neil914]

So I'll try to cover this neatly. I have a '73 2.0 with fuel injection
My 914 does not start cold with the starter motor. Every morning I roll it backwards out of the driveway backwards and then give it a running push down the gentle slope of my street. It will start cold no problem if you bump start it and get the engine turning over at 1,500 or 2,000 rpm. When I cranked the car over for a while I the engine would get flooded and smell of fuel, and then backfire significantly when bump started. Replacing the head temp sensor has helped that, but did not fix the whole problem. The Auxiliary air valve is dodgy and the car often idles high, but plugged or left open it makes no difference. The car used to start great cold and the problem has actually been gradual. When warm the car starts flawlessly. For the first couple minutes of running when cold the engine can die at idle due to the use of the brakes or headlights, presumably because this drops the voltage. I have tried jumper cables from another car to make sure I have plenty of volts but it still doesn't go.
Ideas?
Thanks