Engine Runs Too Often?

[VGP63]

Hello All, I have been the proud owner of a 2009 Gen 3 Prius T-Spirit since June '14. I have always been a Toyota fan ever since I owned a Carina many years ago. I then spent some wilderness years with Nissan & an unhappy 3 years with a Focus. I love the Prius, its a dream to drive & being a bit of a techie love the whole system. All is well but for one thing. Recently I feel the petrol engine starts too frequently. It cuts in even under very light acceleration. I will be traveling at 25mph and hardly press the accelerator & the ICE starts. If fact it's almost impossible to move without the ICE starting. This happens in Eco mode which is what I drive in all the time. Any suggestions?

[Cyker]

It's most likely just down to the drop in temperature. Annoying but nothing to worry about.