Can anyone help me find this book - the details are sketchy to say the least!

[Joekate]

I bought a book years ago for my DS - far too old for him, but I thought he would grow into it if you know what I mean. And now he's ready, and I've gone and lost it!

It's about a wee robot. The book is named after him but I can't remember the name or author. It's set in the future when petrol is so expensive that only the rich can afford it. And I think it's about his journey back to the man who created him.

I know it's really sketchy but I think he would really enjoy it now.

Can anyone help?