chelle, looks like you just purchased the car at the wrong moment...

if i was you i'd look at temp sensors and ignition systems before going into fuelling.

has anyone tryed resetting the ECU?

when my 1.4 split a coolant hose i needed my hazards and sidelights because i was in a dangourous situation, this left my battery flat and the ecu of course couldnt maintain its memory... after that though the flat spot i did have at times for overtaking never reared its head again and i had power all the time... Took me 30 minutes of driving to get it to idle again as it forgot how to idle and just couldnt do it!
(what im saying is disconnect the battery with your light switch on and make sure any system in the car is dead and re-connect after 24 hours turn all switchs off before re-connecting battery though)