Volvo s4o 1.8 gdi 2003 model, I have just cleaned the throttle body and now the car is over reving at 2-3000 revs at idle and surging when driving any ideas please?

Throttle Body Cleaning on vehicles without electronic throttle control (most 2003 and down)

You can in most cases repair this slow speed stall or unstable idle by cleaning the engine throttle valve and the idle speed control valve using a product called CRC Spray Throttle valve cleaner. Spray the cleaner into the air intake of the engine with the hose removed from the throttle body, the engine will try to stall so hold up the idle speed manually. Once you have used up about 1/2 can of the cleaner stall the engine out while spraying and turn the key off, disconnect the negative battery cable for 5 minutes and then reconnect and drive the car for a about 25 miles of varied driving modes. If this doesn't cure the problem you may need the fuel injectors professionally cleaned by the dealer service dept.

Idle air control motor stuck. I would clean the throttle body also. when you replace it.

could be a variety of things, is the check engine light on? possible the throttle sensor is bad, could also be a vacuum leak.

I would check for a dirty throttle body and a faulty idle air control valve.

Still think ot vacuum related .This will push the revs up sky high .Get a good cigar and pulloff a vacum pipe .Take a good puff on the cigar now puff the emoke down the vaccum pipe .Now do you know what your looking for .You got it ,,, smoke ,,,,than you have found the leak.Thats if you have one ..Can you get a obd check it will tell you what it is ..Thermostat removal wont change the engine revs

It is most likely to be the throttle housing and idle control valve that needs a good clean, Gdi's are prone to coking up and cleaning these parts usually solves idling problems!

The idling may be a loose connection to the "idle air control valve". if the control valve connection is secure, then it could also be a bad Throttle Positioning Sensor (TPS). To test the TPS, tap it with a screwdriver while the engine is self-revving, and see if the reving changes when tapped. if its not the TPS, then try cleaning the throttle body.

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You don't mention the model or year, which make a BIG difference.

Possible causes of poor idle:

Vacuum hose leak or intake air intake path leak.

Dirty or loose throttle body.

Throttle body IAC motor is jammed, see above. Fix is to remove the throttle body and clean it.

Dirty air cleaner.

Miss at revs...

Old plug wires or plugs.

Bad distributor coil, will also cause hard start when cold.

Timing could off setting.

Clean or replace IAC valve (idle air control valve).

Check the hoses connected to the throtle bodie.One of them is still out.Found it.