Cold Kangaroo Car

[Giffer2]

Odd one, but ever since I've owned the car sometimes (Not all the time) when driving home in rush hour traffic (Slow, stop/start) and the engine is heating up (normally between 60 and 80) at certain speeds/revs the car likes to kangaroo (lurch), but as soon as she is hot (90) she is fine - Doesn't do it in the morning when going to work as the roads are empty.

I've also noticed recently that when she starts in the morning the headlights dim a little (Never used to) and she takes a little extra effort to start when cold.