Erratic Idle Having Just Changed Battery
 

Hello.

I've changed my 2001 Boxter's battery two days ago(sourced from the OPC, however, a larger one than before), ever since, the idle, both on start up and when the engine is fully up to temperature varies between 800-1100 rpm,the engine works fine otherwise, its just mildly annoying.

If anybody could shed some light on this I would greatly appreciate it.

M