Did you do an ecu reset ? It takes a while for it to 're learn ' the fuel so could be that, just plug the black and green diagnostic wires in then go for a gentle drive until the cel light flashes constantly. Unplug then drive,
Could all be down to the O2 sensor as it will be overcompensating on cold start over fueling until warm.
You need a 22mm open ended spanner to get the O2 sensor off access is a bit tight