sounds to me mate like its one of them dodgy chips that makes your car think the engine is cold, therefore sending more petrol into it, therefore using more petrol. like the automatic choke is permantantly being used..
Its more or less the same effect that I had when the temprature sensor was broken, I must say that the car actually seems more powerful, but the fueleconomy is VERY poor. Its probebly using something like 30-40% extra fuel, atleast it seemed like this when I had to go fuel the car all the time .
"they are all printed onto the finest quality blanks availible"
Print, onto a ROM? Get the terminology right!
Read his feedback... He brought something off a German and then was astounded when there were communications problems because they seller spoke German and he obviously doesn't (at least not enough).
The description says "Fiat Punto 1.2 16v fase 2 ecu Magnetti Marelli (1993-2001)", so it might be better to clarify with the seller if it will work with your Mk2. If he's genuine he'll answer how it works - it's his business to sell them, but he can stop the code from being read and used by someone else.
Punto Mk2 ELX 8v in Teseo Blue with the electric Sunroof and CD changer, doing 50mpg whilst passing down country lanes