I've noticed that if i leave the car off for a good 2 or 3 days and then try to start it with the engine coolant temperature sensor plugged in - its very hard to start.
But if before starting it i unplug the engine coolant temperature sensor, the car starts like a dream first try and does not stutter.
I got an OE Bosch replacement sensor as i thought this was a problem with the original one, but this issue still persists.
The wiring harness was redone in 2010 by a reputable individual, so i don't think there is anything wrong with it.
Could be the ECU maybe?
Or maybe the actual connector for the sensor is faulty?