2008 Smart ForTwo shudders, but no fault codes

My 2008 smart (43000 mi)has started to give problems starting. On first start in the morning it starts, runs a few seconds, then starts to shake & shudder like it wants to die. Then it smooths out & runs fine & starts fine the rest of the day. Can you help my mechanic diagnose this? He says there are no fault codes in the OBD that might indicate the cause of this.

Have your mechanic clean the electronic throttle body to see if that helps.