I have an 07 Prius PKG 5 with 30K. The car has performed great up until now. Over the past week or two gas mileage has dropped into the 30's at times--38-40. I have not changed anything. Oil levels are fine, tire pressures are fine, etc. I notice that the battery stays green quite a bit...I read somewhere seeing a green battery is rare. I live in south Texas and it is cooler..but it's not crazy cold. Temperature has been in the 50's. Something isn't right. The electric/gas motor isn't coordinating as it should. To the dealership?? I can cruise at 60 and the meter is hanging in the 40's. Every now and then it will register higher mileage...say going down a hill or decline, but on level roads, nothing like before. Help appreciated.