Transmission problems??

If there is no engine light or RTOD this is probably the car doing what it has always done. As there are no clutches or torque converter, it is impossible for the transmission to be slipping. If you have not done so, you could get the spark plugs changed. I believe what you are feeling is related to the ICE starting up. You could take it by an AutoZone or Advance Auto and get the codes scanned, or you could look on the net for Techstream, if you have a laptop to run it on.

 

how many miles on her? at some point, they need maintenance that goes beyond the o/m. not all issues give trouble codes

 

RTOD Red Triangle of Death. ICE Internal Combustion Engine

 

I've been here a while, and the only one I know is that $@&%!! ICE, which equals Internal Combustion Engine, or Engine, which used to work just fine.

 

Anytime I hear "transmission slipping" in a Prius I know that you don't know how the vehicle works in its most basic sense. That's fine but then we have to ask questions because what you're saying doesn't make sense.

As explained in the first post, the Prius has no transmission. No torque converter, nothing to slip. It's a single planetary gear that is always engaged and it has static gearing. Even in reverse, nothing moves/changes other than the rotation of various parts.

Most times "transmission slip" in a Prius means that the HV battery is low or hot and the power to the wheels is severely limited. This makes it so that when you hit the pedal it lurches forward momentarily (whatever small charge the HV battery does have), then it "stalls" in acceleration as the ICE (the gas engine) spins up to higher RPMs and starts making power, and then starts accelerating.

This happens when the car can't pull power out of the hybrid battery. This happens for various reasons. The most common is the battery is depleted. If you look at the energy monitor display, note how many bars the battery icon has when this happens. You should drive with this screen as your default so you can make note quickly. The other option is that the battery is too hot and the car is limiting the power out of it to protect it. But being the middle of the winter, this is less likely.

 

have you done things like throttle body and maf cleaning yet? injectors, etc?

 

This definitely sounds like the best fit for the symptoms you describe, @GETAKLU. Check out that battery icon when it happens. I'll bet it's down to two purple bars or lower.

 

Ok, you have put 60k in the last 5 years. But how many total miles are on the car? It could just be time for spark plugs, or you could be on the threshold of a failing battery. That brings me to the next question. What are the weather conditions now compared to when you first got the car? Climate control settings can have a huge impact on the mpg. Keeping the inside temp at 71-72 versus 75 will cause the gas motor to run less, as well as running the fan speed slightly lower too. Also the mode where the air is coming out. Defrost only will run the engine more then defrost/floor mode.

Tire pressure, it only takes a 2-3 psi decrease to start affecting mpg. My car is a Gen 3, but I run mine at 40 psi. And if the temps hit the 50’s and hold there for a week, then drop into the 30’s for a week, then recover, you have lost that 2-3 psi.

Jack up the rear tires one at a time. Give it a decent spin. Have a helper apply the brakes a couple of times. See if it spins any differently. Then apply and release the parking brake. Spin the wheel again. If there is a noticeable change on a wheel, that brake may be dragging.

Check these out and let us know what you find.