I have 2006 Focus mk2 and when the car is below 20km/h, i press on the accelerator but instead of push the car forward, it just cause the rev to go up to > 2000 and then change the gear (not sure it move up 1 or down 1 gear). The service centre has changed the ATF and also reprogram the ECU but still has the problem. Could this be a faulty ECU instead of a bad s/w program.

Is the car still cold when this happens?

If yes, then it is just the car's way of heating up the cats in the exhaust. When cold it will hang on to a lower gear for much longer, this increases the engines revs, increases the exhaust gas temp and flow volume which then heats the catalytic converter up to the normal operating temperature.

Every automatic car I've owned does this when cold in first gear at raods speeds that you mentioned.

Once warm it goes away.

Any other faults with an autobox can usually be attributed to low transmission fluid. A Ford dealer should be able to tell if the autobox has the correct level of fluid in it.

HTH

Andrew

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57 Ford Focus 1.8i Zetec, the wifes.
04 BMW 545i - My current set of wheels
53 BMW 545i - Stolen from a BMW dealer
S BMW 523i - Not quite enough grunt.
H Vauxhall Senator 3.0i 24v CD - left Golf GTi's at the lights
H Rover Mini Mayfair 998cc