Lack of power at low revs

Got in my 99-T 1.820v (non-turbo) Octavia to come home from work tonight, and there was a lack of power at low revs. In gears 2-5, if you put your foot down, it struggles to accelerate until it hits around 3000rpm, then carreis on as normal. It also doesn't feel quite as bad if I am changing down gears. I drive 25 miles home from work, so it had plenty of time to warm up, but it was still struggling at the end of the journey. Can anybody shed any light on what the problem could be? Thanks.