Hi all, my Fiesta is struggling to maintain idle speed when first started from cold. I have to keep my foot on the accelerator ticking it over until the second bar comes on the temperature gauge. After that all is good and the journey continues ok, engine running normally with usual performance.

Had a search around the net and one of the first port of calls is splits in vacuum hoses, so I check under the bonnet and low and behold the vacuum pipe running from just to the side of the alternator and running behind the air intake manifold has a split and is hissing.

Fine I thought there's the problem but when I put my finger over the whole the engine stalls, so i replaced the hose and now it won't keep at idle speed even when warm, as soon as you take your foot off the accelerator it stalls, put the old pipe back on with the hole in and it goes back to idling when warm, stalling when cold.

Help needed please.

Cheers.

Look for more split hoses - or even completely missing hoses. I had a similar situation when the vacuum hose to the PCV valve came loose. Pay close attention to any hose with an elbow in it. Listen for any hissing sounds. If you're at least slightly crazy, spray the engine bay with ether (may be called "diesel starting fluid", you can also use brake or carb cleaner but it doesn't work as well). If the engine changes pitch / RPM, then you absolutely have a vacuum leak, keep spraying to find it. My Ranger had a cracked PCV valve hose and bad gaskets on the intake air manifold, which was a bit of a chore to repair.