Fiat Duo

As if one diesel Uno isn't enough we bought a petrol version last month. Coming back from Alicante the other day on the motorway I stopped to top up but the garage didn't sell 4 star. I had to buy unleaded, plus some lead substitue which bore untranslateable instructions. Poured in half a bottle and it went singing off into the distance. However, three days later there's more lubricant getting through than petrol and it keeps having flat spots and refusing to start. Produced a cloud of smoke worthy of burning tyres today. Still, all's well that end's well and we managed to limp home despite a number of false start rescue attempts. So, what now? Change the plugs? Clean the carb? Siphon the tank dry? Who knows? Presumably it'll pass through in time. What's your advice, Steve? Dad says you are the Uno expert! ps. If you want a free 1993 diesel 1700 2 door right hand drive with British plates, there's one in our garage that runs well and can be driven away by anyone who feels able to get here. Free to good home, as they say. Brakes need a bit of work, to tell the truth and unfortunately the ownership papers have been stuck at the DVLA in Swansea for the last six months which is why I cannot use here without running the risk of a fine, being resident and all. Not so if you are a tourist though....