My 2000 Ford Focus (Zetec, auto, air) has started to require some throttle to start and keep running when the engine is cold, even in relatively warm weather. If I hold the rpm at 2000 for about 30 seconds, it will usually begin to idle normally, but sometimes not for 5 minutes or so. My shop can find nothing wrong. Any ideas?
There’s a good chance that the problem is a sticking idle air control (IAC) valve. These are usually not too hard to pull off and clean. A cleaning may help or you may need to replace it.
These cars also have a lot of problems with the PCV where the line goes into the intake manifold. The hose part of it virtually turns to mush. Could be getting too lean when cold. Is the check engine light on?
Did you leave it overnight, so they can try and start it in the morning to replicate the problem?