Update
2 mornings now and car seems to be running fine, sorry to read and hear you still have troubles. I find it frustrating when I don't understand a problem and with these cars it so difficult to do much yourself without diagnostic equipment.
I know the petrol focus is not that great on petrol as a guy has one at work. This is my second Mk Zetec S as last one got wrote off after being rear ended. I could have brought the Mk3 but didn't like it when I had a courtesy car you tend to sit low down or the dash is that much higher.
The zetec s has quite a stiff ride but it goes round corners well!!!
I never really checked mpg with mine but wasn't impressed the other day when I put £10 when light came on and came back on next day having only done 70 miles. I should point out I was doing 90mph on dual carriageway most of the way as was I late for appointment. Have had better mpg when I went to Lake District and averaged high 40s.
What problems are you left with?