Hello all... got the fast idle 'feature' with a '99 1.6 LX, symptoms as follows:
Car starts and runs fine when cold – problem only occurs after about 15 minutes driving.
Revs very slow to drop between gear changes.
Engine braking virtually non-existent.
Put car in neutral while moving and revs sit at about 1500.
When coming to a stop revs sit at about 1500 until completely stationary and then drop to 750 after a few seconds.
If speed increases while in neutral (e.g. downhill) then revs increase accordingly up to about 2000.
But here's the twist which I haven't seen mentioned whilst trying to research the problem: if you roll in neutral and put the air-con on, when it kicks in the revs drop to a steady 750. Turn the air-con off and they increase to 1500 or above again. You can merrily switch the air-con on and off and the revs decrease and increase accordingly.
I wondered if the air-con 'trick' pointed to a particular component at fault? From what I've seen any one of the vehicle speed sensor, throttle position sensor, idle air control valve or engine breather hoses could be the problem and I'd rather replace the correct component than buy something that's not required!
Any help much appreciated. Thank you.