Whilst giving the car a much needed minting inside, i checked under the bonnet and even this was full off dust etc, so i thought i had better just check the aircleaner and inside the box i found a pile of mouse nesting material mixed with some airfilter material and the remains of two baby mice! How long these had been there i don't know, the car is always in use and there was no noticable loss of power!  It only takes a few mins- check yours!