Please help my fiesta's driving me mad!!!!

Hi My name is Jane and i have a red ford fiesta, its 1.4 zetec 2002 petrol. I have had it for about 6 months now and its played up since it was bought. It doesnt start and this mostly happens on cold mornings. Sometimes when i get it started there are no revs and it just sits and rumbles and shakes . If i rev it, it either still shakes and rumbles or cuts out on me. Its been in the garage so many times and its been back to ford itself. It has had spark plugs changed and a front sensor on the exhaust also. When i go to the garages with it and i tell them whats wrong they say there is nothing wrong with it and basically i am lassie and what do i know about cars.

I cant afford to buy another car.

It sounds like it needs a good service. Has the air and fuel filters been changed?

Is it OK when it has warmed up. If not it may need new HT leads as well.

I would give the engine a full service including above items as well as an oil and filter change. Put a bottle of REDEX or Cataclean in the fuel tank and take it for a good blast at motorway speeds for around 30 miles. That would clear the injectors and any soot off the sensors

It will do it the world of good

It has had oil filter changed. When its on the move its fine but it can play up, like if i got shopping or that i switch the engine off and go shoppin and come back it will sometimes do it. I will give it a shot by putting the REDEX or the cataclean in it and give it a good blow out. She was owned by an elderly couple from new and only did about 30-40 MPH which mayby hasnt helped her.

Thank you for your advice :D