got myself a 1.4 zetec fiesta about 6 months ago and with full history and all that stuff it's been absolutely mint, other than a small problem that just won't quit

when it's cold, below 60 degrees water temp, the idle can be as high as 1400rpm, which is a shit because the gearbox doesn't want to get into 1st or reverse and now it's crashing in the gears even when it's warm

this morning i took the top of the car apart to change the temp sender and found that the old one was fubar, the grey plastic bit was spinning in the copper bit



new part installed there was also an issue with the plastic inlet pipe which is split as you can see



but it's also breathing real heavy, just look at the state of the breather hose filter



but the air filter is spotless as is the rest of the engine bay, even the caps are clean (until i put my oily hands on one of them and it's now dirty yellow )

with the air system off, i started it up and the same, 1400 rpm, but with the pipes now off i poked my finger into the butterfly flap and it was covered in oil



so, any other ideas?

or do i just leave it as it is now?

 

air leak somewhere on inlet or pipes,

ie a split pipe/vacc/breather hose,

 

Idle speed control unit?

 

i expect theres a breather pipe that goes to the air box/inlet hose which will cause your oil in the throttle body.. maybe worth spraying some carb cleaner in the TB, the oil maybe making it stick/not close properly?

 

but why would it then suddenly be "fixed" when the temp reaches 60 degrees?

i'm going to stick some carb cleaner in the next time i've got a day off and also change the pipe to eliminate that problem

one thing i did discover though is that when pressing the butterfly flap there was a "clonk" and if there was some play somewhere in the system, but it's all new fangled stuff so i'm not sure if it's related or not

 

the throttle body bloody expensive to to buy but seems few with similar problems

 

From memory the idle speed is controlled by the throttle body unlike the earlier Zetec SE that had a separate valve on the inlet manifold. It may be a cold start setting that keeps the idle slightly higher in the ecu.