Interesting to see that I'm not the only one who's had this problem. However, the car's now done 32000km and I don't even remember when the problem last happened.
I think the previous comment was probably correct in saying that this problem is probably due to the gearbox needing to loosen up.
I'm still very happy with the car!
My Picanto's now done 37,500Km. Around 35,000Km, one of the rear registration plate bulb covers broke off when closing the boot, but was replaced for free under warranty.
Other than that, it's still going strong.
The car has now done over 70,000Km and survived its third Finnish winter. Rear disc brakes were just replaced. Other than that, all's well.
The car has now had its 95,000Km service. Rear pads were replaced again, and the camshaft timing disc was also replaced free of charge under warranty.
One negative thing, though: in cold conditions, the car's front suspension now squeaks when decompressing (meaning going back to its normal state after driving over a bump). This started in autumn 2008. I changed Kia dealers for the 95,000Km service (because of job relocation) and wasn't happy that they couldn't also fix this suspension squeak problem. I was simply told to 'drive carefully' as they claimed their testing machines couldn't find any faults. Personally, I think it's a worn suspension bush, but I'll take it to a local independent service station once the squeak comes back - it always goes away during the summer/warmer weather.
I'll write an update about this once the problem is finally solved. I'm still happy with the car, though. It's driven close to 100,000Km now so I accept things like worn bushes as normal wear and tear. However, I won't be returning to the same Kia dealer, though; I'll return to the original dealer - even if it means a longer drive.
The car's now driven 122,000km and still going. The suspension sound still appears during winter, but I've learned to live with it rather than give more money to a dealer.
The car was involved in an accident at the beginning of the year and had driven 132,000Km. The car was written off, but the driver (my wife) was able to get out of the car with nothing more than two bruised knees and a bruised ego.
In my book, the car did its job properly and the passenger survived - so don't believe everything you read about cheap cars. This one did the job perfectly.