Sudden drop in mpg

I tried to read all the drop in mpg threads for the Prius prime but none really seem to match up with what I’m experiencing.

I’ve always averaged 59mpg. I don’t plug the car in because I live in a condo that doesn’t allow chargers and 59mpg is more than enough for me.

Well here is what I noticed. One night it was in the low 60’s so I decided to turn on my heater, there was a huge clunk sound from the driver side of the engine compartment, I thought that was strange but wrote it off because it was quick clunk and no other odd noises came about after that.

Well I’m driving on the freeway and I notice the mpg is in the 40’s on the freeway. I’m in eco mode and I don’t drive aggressive. Nothing has changed in terms of driving habits, tire pressure, the temperature was 5 degrees cooler than normal. The heater was only on for 5 mins to warm the cabin up just enough.

Since then my car has felt weak starting from a dead stop. It’s like there is no power. The engine is constantly kicking on even when I’m just at a dead stop. I read about winter gas but the problem started mid tank, so there was no new gas. My car feels like it struggles to even go up the slightest incline now. There is a noticeable difference. I’ve driven this car for the better part of 12k miles and I know I’m not going crazy. There is definitely a drop in power and a huge drop in MPG. I tried driving normally and it showed I was getting 38mpg, this is in ECO mode. Tonight, I tried to watch my gauges and tried to get 60mpg. I managed to get 51mpg but I was crawling down the street.

From a stand still, If I barely tap the gas pedal the gauge shoots up in the “red”. It never did this before. I want to take my car to the dealer but there aren’t any cels or check engine lights.

I’m sorry if I don’t know the terms, this is my first Prius. I definitely think there is a performance issue with the traction battery.

Has anyone else remotely experienced the same problems?

 

Thanks for the reply guys. It was really helpful. I canceled my appointment today because I didn’t want to go there and not know exactly what to say. I’ll remake an appointment and update any findings.

I was starting to settle with the colder temp and winter gas theory. That clunk was not normal and the loss in mpg was most likely the result of it. Nothing else has changed or happened.

One more thing, it’s not related or maybe it is. I read the manual and I couldn’t find anything about not taking the car into an automatic car wash. I’ve been taking my car at least twice a week. I’m wondering if that could have caused a mpg ticking time bomb.

Thanks again!