I have had this problem for about 2 months now. Car makes a grinding then rattling noise on initial start up after its been sitting awhile. The first time i took it in, nothing was found. The second time, a roundabout solution was found. Third time (supposedly a charm) they replaced the acuator, bolts, and some other miscellaneous parts, problem still exits ($860 dollars later). If anyone has any knowledge of this problem please help...It sounds as if the vehicle is struggling to stay crunk...