My zetec (1.25) is "missfiring", recently changed the plugs and the coil pack as suggested on several websites including this one, ran fine for a couple of days and has started doing it again. Basically its fine at speed but it dips of when accelerateing, i noticed as well that there was Furring on contact 3 of the coil pack when i replaced it, but thought this was just due to the coil pack being knackered. can anyone help as this is really doing my head in

 

Is there any CORONA DISCHARGE ?
Try using some SILICONE GREASE on the inside end of the plug caps.
tabetha

 

Ha ha. This happened to me 1.25 zetec Fiesta and it turned out to be a dirty MAF sensor. This is located in the metal bit closest to your air filter. A cotton swab with some meths on should do the job. Mine reduced in size about 10times after cleaning. Just be careful you don't use too much pressure as it's quite 'dainty'.

My car ran like a dream afterwards.


Hope this helps you!


Pete.