Zetec 1.8 misfire at around 1500 revs

[Tunku]

I had this problem, engine stumbling under light load in traffic. Misfire at around 1500 revs in any gear. Get revs up and no problem. Had a read of the manual and online stuff. I came to the conclusion it was HT leads needing replaced. I had the Ford ones on, and replaced them with the Ford ones (Motorpart). Misfire now gone, and pickup better than it was too. £33.00 plus Vat. Result, I'd say.