'89 Charade 1.3 EFI problem

Forum: 

My '89 Charade 1.3 EFI is driving me nuts! In the mornings, it starts and runs fine. When I have driven a few Ks' and stop somewhere for 20 mins or more, it is really hard to start again. It will turn over fine, but takes about 30 seconds of turning over before it starts to chug and belch heaps of black smoke. Then it will run really rough for about 5 mins before settling down. When it is running rough, the engine warning light comes on, but at no other time. It will sometimes stall as well, and be really difficult to start(same symtoms as previously mentioned). I have taken it to a mechanic, an auto elec, and a fuel injection speciallist, and all cannot get to the bottom of this problem. HE-E-E-E-E-E-E-E-E-E-E-E-E-LP!