Mk1 Focus revs when coming to a halt

[tonyvid]

My other half has a '99 1.8 petrol Focus that kept stalling when coming to a halt. I couldn't look at it for a while so she took it to here local garage who cleaned the idle control valve and this made it rev for a few seconds when coming to a halt - they decided it needed a new one instead but this still makes it rev when coming to a halt. It revs to about 2k then drops when you finally stop. The garage "didn't know what was wrong and just use it for a bit, love"

I had a look around a found a collapsed and manky crankcase breather hose, new one popped on but it still does it... Gave it new plugs etc at the weekend, disconnected the battery for 20 mins and then started and let idle for 15mins - it still does it!

Any ideas? Have they disconnected something I haven't noticed or fitted the ICV wrong? Funny how it had one fault and now has a different issue Someone has mentioned the gearbox mounted vehicle speed sensor could be faulty but there are no speedo faults(it is an early one so might have an additional cable). The speed sensor could be at play because the revs go up as soon as the throttle is lifted/clutch down and drop again almost as soon as you stop. It does seem to have a form of free cruise control now!

[JohnWest]

My 2000 1.8 Focus also does this. Although after a couple of minutes after start-up from cold the revs no longer rise before falling. I know exactly what you mean though, as you come to a stop the revs would rise, mine occasionally hits 3000 (!) before settling down again.

I too had a collapsed PCV hose. But this hose was causing my car to idle very lumpy and on some instances stall. But then the well known issue of the speed sensor failing hit, meaning when I was slowing down to a stop the revs would drop and car would cut out. It was pretty consistent at stalling, did it every time. Sensor changed, stalling issues went away.

[tonyvid]

Hi, thanks for coming back. Looks like I'll have to give the speed sensor a try - I've been reading that some are right sods to get out and break leaving a whole load of trouble so I might try to find someone experienced to do it....first job is to disconnect it and see if it is actually doing anything useful!