iv got a mk 3 polo i think lol

its a 1.0 with a 4 speed box single point injection

when i start the car up in the morning it miss fires and throws loads of black unburnt fuel out the exhaust

but when the car gets up to temp it runs spot on and dont miss a beat

iv changed the plugs and leads

the two temp sensors on the thermostat housing

i think I'm gonna end up changing the spi unit

does anyone have any info on what could be the problem

Might be worth checking the lambda probe