At the last service a couple of months ago (59000 miles) I asked the mechanic to investigate what I can only describe as "hunting" at tickover or steady low revs. No fault codes were identified and the mechanic suggested that "air may be getting in somewhere and the engine management system is trying to compensate". Since then on a number of occasions I have experienced a temporary reduction in power when under accelerating load at about 3000rpm. This appears to clear after easing off the accelerator. I would very much appreciate any suggestions that you may have. My journeys are typically 10 to 20 miles each way with a good number of longer trips eg 30 - 50 miles. I always try to give the engine a burst at about the 3000rpm mark.