1997 Vauxhall Astra cold starting

Sounds to me like your choke's not coming on from cold,if your diagnostic check was done with the engine on running temp it would not show up this fault,if you stop after a run,and the car starts to cool down,if you start the car and your symptoms re apear,after running fine on running temp,think it must be favourite

temp sensor, had the same problem. And also ther was a wire loose from the starter to the ignition, which still let the car turn over

Possibly coolant temp sensor, have the voltage of it checked when cold, it should have 5 volts supply and up to 4.5 volts coming out of it when cold. other possibilities on this engine are sticking valves also check for air leaks

have you tryed before starting up is to press the gas peddle in a few times then put you clutch fully down and start? if not have a go i have to do it every day in my cav. i get the same problems special on cold days. it starts like a light i not sure what it does but it does work and a friend who works in a garage told me to do it when he found nothing wrong with it!!!!

do not hold the gas peddle down you may flood it it is the clutch you need to hold down!!