would changing this make my revs drop straight back down to the proper idling speed as at the minute it hangs at about 1100 rpm to 1500 rpm then eventualy settles at a lumpy 1000 rpm the car shakes a bit :S
engines mounts are all ok ..
Similar yeah. Occasionally reved itself between 1500 and 2000. Give it a few big revs and it will sort it. Becomes extremely embaressing when you stop at the traffic lights and look like you constantly reving it!
Got my new icv for £25 off ebay so pretty cheap too.
catch it when the idle is right and pull the icv plug off quickly and it should stay rock solid. If it still does it the icv isnt the problem.
If you disconnect it while the engine is not already running, it will rev and idle weirdly since the icv parks itself when the engine is switched off and the throttle plate has play in it when the icv is parked, the best solution is to catch it like i say when the idle is right, and pull the plug off with it running, it will not move after that (on its own) as its a linear actuator motor like a little rack n pinion so keeps that position for ever once its set and disconnected.
One common fault that will mimic this, is if the tps (throttle position sensor) is wonky, the ecu will keep playing with the icv trying to match what the tps is telling it, and disco'ing the icv will stop it from being able to alter the idle from where it is at when its disco'd, the tps will still tell lies, but you wont see the effects of that anymore. In this instance, leaving the icv disco'd will make the car run ok again, but replacing the icv while you have a still-faulty tps will just cause the problem to return. Just worth noting! The tps is a little black box attached to the throttle body that reports the throttle position to the ecu.