Rav4 2001 Rough Idling

[xzulu]

Hi I'm just new in this site, i'm from the Philippines. Anyways I have a problem with my Rav4 2001 w/ 1AZ engine w/ 57,000kms already. Anyways I brought it to Toyota to have it checked and they found that one of the oxygen sensors in the exhaust manifold is not responding properly to the OBD. So they replaced it with a new one. After that the idling was normal. The next day after i brought it home I used the car for the whole day and the Idling started playing around again. It idle's around 500rpm, lot's of vibration, and the engine dies when i turn on the aircon. And when making turns the enginealso dies. So i brought it back again to have it checked, so thy plugged the OBD again and they found nothing....What could be the problem? Well, as of today, they removed the throttle body and cleaned it because they noticed carbon was building up. They cleaned it and the Idling became smooth again. I'm just afraid that the problem can occur again.

could it be the fuel filter? they said the fuel filter is normally replace every 100,000kms

[xzulu]

Help Please!!!!!!

[Dame]

Your best bet is to sell the Toyota and buy a Land Rover, says my brother.