Hi all, I have bought my better half a 2000 1.8 petrol focus as her first car and I am having a few issues. The car runs great when cold but when it starts getting up to temp' the problems start. It will idle around 600 rpm and miss as it is stood. Also when driving anywhere between 1 - 2000 rpm it is down on power, coughs and judders. As soon as you get above 2000 rpm it starts to behave itself. I have changed the HT leads (after getting a shock off one) and plugs. I also found a split PCV hose which I replaced. I have had a look at the MAF sensor and it looks very clean. Any ideas would be great, unsure if there are any methods for testing the MAF with a voltmeter just to make sure?

Many thanks.