Strange problem... Or is it?

I have a 2004 bought in 2003. It recently logged its first 100k miles. My problem with it is not easy to describe. It is actually running more like a non-hybrid car. I can feel and tell the hybrid system is operational, and I can hear the electric motor whine when coasting, down, etc. However, I don't think it is running as it should or as it used to. It happened on highway while cruising about 70 mph. I hit the accelerator to pass someone, and I felt that something changed. I'll try to describe it: think of a half-clogged pipe. The water can barely gets past the obstruction. You keep applying pressure, and suddenly the clog dissolves under pressure, and water begins to flow freely, and the pressure goes down. So it felt like that. Now the accelerator pedal is lighter, car is faster to respond, yet I think something is wrong because the car isn't itself anymore.

I don't like problems like these because they are very difficult to diagnose, let alone fix. For a while I also have not heard the inverter pump whine after shutting the car off as I did in the past, but the last time I got out of the car today I heard it. I believe it was replaced five years ago after a collision with a Trailblazer wiped out half of the front end ( but with no power train damage, thank goodness). I checked the VIN for the inverter pump campaign, but my VIN was not in the range.

Right now my problem is that the car feels a lot faster than it has ever been. When I lift off the accelerator, it doesn't begin to coast as it used to. No warning light of any kind out of the ordinary is present on the dash, although it did have the red triangle on during start up with a message about the parking gear not being engaged properly. That warning went away after the change in performance occurred. Related?

Has anyone experienced anything like this? I guess I will take it to the dealer to see if there are any codes stored, but I wanted to run it through here first to see if anyone has anything to say about it.

Thanks in advance

UPDATE: After my 30 mile commute this morning, no whining, buzzing or any kind of noise was present after I shut off the car and I got out. There is still no warning light.

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No difference in mpg as I can tell. I have to say, though that the ICE is more eager than before to kick in.

And yes, I think that is the noise. What concerns me is the lack of it. I am used to hearing it all the time, so now when I don't hear it I think something is wrong.

 

Yeah, I am still on the original battery. I will test when I get a chance, or even just opt to replace it with the Optima YT, but that warning has gone away since this change in performance occurred. Also, my mpg is unaffected.

I am mostly worried that the car isn't operating the way it should, but since it's not giving me any warnings, not sure what to do about it. Can there be stored DTC without any warnings in the dash?

 

102000 miles. Just all the usual maintenance plus the repair after collision. It goes in every 5000 miles. All recalls, save for the steering and floor mat, have been done. It was not in the range for the Inverter pump campaign.

 

That's what I figured. Some other points to note:
1. Throttle body cleaned 2 services ago. Dealer wanted to do it again the last one, but I did not think it was that necessary in 5000 miles.
2. Two visits ago, the dealer told me the water pump had a small leak (don't know which one, and I forgot to ask), so the last time I took it in, I was prepared for them to replace it. I requested it on the service paperwork when I dropped off the keys, but the mechanic called and said there was no leak. So no pump was replaced.
3. Brakes checked out, each time, and I am still on the original pads/shoes.
4. What belt are you referring to?

 

Thanks. I think I have weekend project. I tested the battery, 11.6 down to 11.3 when I turned on a few things. So the battery replacement will be done first.

I don't have resources to do flushes myself, so I'll have to take it in for those.

 

Holman Toyota in Marlton. The car has been serviced there since new in 2003

 

Update: I replaced the battery yesterday with the Optima YT, and the car has returned to normal operation. save for the driver's side window auto up/down.

I checked the inverter pump and it is working, so no issue there at all. I guess I got my money's worth out of the original Prius battery. It was in there 9 years and a few months.

Thanks for your help, guys.