Mondeo holding revs...

Probably a vacuum leak. Check hoses and listen for air whistle around the engine. Also check electrical connectors to Air Mass Meter and other sensors.

Thanks for that.

TBH, I think that added to a couple of other jobs that need doing, it's time to punt it on elsewhere, as it will cost more to fix than it is worth (to me, at any rate).

This sounds very like my Fiesta 1.25 Zetec. Symptoms exactly the same.

In my case it was a broken wire on the power steering pressure switch which was confusing the ECU. Basically the ECU was thinking the pwoer steering fluid pressure was too low so it was increasing the revs to counter that.

Try temporarily disconnecting the Vehicle Speed Sensor - that stopped the problem with mine. If you find the problem then goes away that would indicate to me that the problem is electronics rather than air leaks or similar.

Tony

In message , Tony Brett writes

Well its actually there to increase the revs when power steering is being used but its much the same thing as you described.

Oddly enough the Mk1 Mondeo is very prone to the fault you described due to the wires on the switch being very close to the bonnet when closed. I don't think it raises the revs by that much though, only a couple of hundred revs.

The OP's problem sounds TPS related to me.

Yes but it was thinking the pressure was low because the cable was broken, not because it was actually low!

And on the Fiesta they almos drag the ground - hence same problem!

Yes - everyone said that to me. It was neither the TPS nor the ICV. The clue is in the fact that the revs are OK once the car stops moving - I don't think you'd see that if it was either the TPS or the ICV.

Another test to do is to park facing down a hill and just let the car roll forward (with the engine idling but not in gear). If the revs increase of their own accord then I'll put money on the Power Steering switch being the problem.

Tony

So is this a normal feature of cars with power steering? I have had this change of speed with my other car - a Chrysler Neon - ever since I got it over three years ago. Normal tick-over is set at 1000 revs, but as soon as I touch the wheel it pops up to 1100. Can I disable this feature?

In message , The Enforcer writes

If you can locate the switch which will be in one of the power steering lines, I would imagine you should just be able to pull the electrical plug off.

Hmm but you do that on a Fiesta Zetec and you get the over-revving problem. The switch signals low pressure by going open-circuit. You need to remove the plug and short circuit its contacts.

But the whole point of the switch is to stop then engine stalling (by increasing the revs) when the power steering demands more torque than the engine can give at idle when parking.

Tony

OK, but on mine it is too much, leading to irregular tickover and juddering at low speeds. How do I find this connection??

It will be a pressure switch probably screwed into one of the pipes that carries Power Steering fluid around the PAS system.

Tony