Fault code help please

[mdibb2009]

Hi guys, the car keep idling funny and when the engine is under a bit of stress, such as going up steep hills, it seems to loose a lot of power, the revs sometimes drop for a few seconds then go back up.

There was no management light on so I read the codes and got :

P0170 Fuel Trim Malfunction (Bank 1)

Any ideas what this means please guys ?

Thanks very much

The car is a 1.8 LS by the way

[sb1uk]

Hi This code points to the 02 sensor on bank 1.

[mdibb2009]

Thanks very much for the reply mate, is this easy to change ?
Ive a bit of experience behind me but this is the first time ive had a vectra.

Also the car seems to idle quite high when first started, then drops back down, and sometimes its quite up and down when sat at lights etc.. would this sensor also cause these faults ?

Thanks very much