I have a 2009 prius that I bought in March. I have not had any problems with it until yesterday. I have been averaging around 53 mpg, but yesterday I started having problems. My prius is not maintaining its speed, it is making reving sounds everytime I accelerate, and it is using way too much gas even when I am gliding. I have not changed how I am driving or doing anything different, but my average has dropped to 35 mpg. I am planning on taking it in, but I thought I would go ahead and see if others have had the same experience. Any ideas?
This sounds a lot like a failing HV battery. Have the dealer test it. Sometimes a failing 12V battery can cause other weird problems, so I can't rule that out, but the symptoms sound more like the HV battery. Tom
It wouldn't be a bad idea to double check you tire pressure. If you have had colder weather recently it can make you lose quite a bit of TP.
