Dear Forum members.

I have a 1.25 fiesta Zetec which won't idle AT ALL when cold. It doesn't even try. after 2 mins it tries to idle, then after 3 minutes or so it idles fine and smooth. No hunting at all.

Once warm, if I rev it the revs come straight back down to 750 ish and does not dip lower even for a second.

I have tried spraying WD40 and brake cleaner around all vacuum conections to see if engine note changes but engine note doesn't change. 

Any help would be greatly appreciated.

Any lights on the dash? Even just occasionally ? I had a 2012 cmax which had a similar issue, would die occasionally after a few minutes, very rough idling. Had the camshaft position censor replaced and fixed it, but could be spark plugs or or some other sensor.

 

Thank you for your comments.

I'm sorry I forgot to mention there are NO lights on dash and NO codes on OBD reader. Also, If I drive it in those first 2-3 minutes when it won't idle it does run a bit rough up to 2000 revs. When warm, it drives fine and smooth

I'm an idiot. It's a Duratec 1.25. Not a Zetec.

I'm going to connect my scanner to it when it is stone cold to see if any sensors are reading way off then reading ok after 2 or 3 mins.

I've had that before where a water temp sensor read -40 when cold and suddenly jumped to correct reading at about 20 degrees.

Any other recommendations would be gratefully received.

I connected my Foxwell scanner today when it was cold and started the car. While the fuel system was running in open loop it won't idle at all. All temp sensors seem to give accurate data. As soon as fuel system switches to closed loop ( after about 3 mins) it idles as smooth as silk.  Both O2 sensors are saying Lean but I can't find any fuel trim readings on my scanner that might tell me if I have an air leak. 

Did you ever get to the bottom of this issue? 
I have a similar problem with a family members 2007, 1.25 fiesta, plugs changed but no change (but it did need them doing anyway) and after changing the plugs I decided to plug my code reader into it and it displayed two codes; P0325 and P0324, which relate to the knock sensor and communication to the knock sensor.

Does anyone have any ideas as to if the error could still be on the ignition side, as I’ve read that ignition problems and sometimes through the knock sensor codes, or is it definitely the route of the knock sensor?!

Apart from changing the plugs has any other work been done on the engine?
You could try removing fuse 16 for a couple of hours, this should reset the PCM's learnt values.