2013 Prius losing power on hills

Too much drag and resistance to go fast. Engine was revving high but gaining speed slowly. Now, THAT is NOT normal. I inspected my car.

 

It's possible there are more than one issue.

This is a serious symptom, typical of a head gasket leak causing low coolant OR a serious vacuum leak if it was egr work related. However overheating due to egr work is unlikely.

How was this resolved?

Overheating has been known to cause limp mode and may not code because of a lack of coolant at the sensors. This should be obvious with low coolant in the passenger side reservoir. A failing water pump is also possible.

A failing inverter could cause limp mode but will code and throw warning lights. The inverter related software update was intended to reduce the stress on the power electronics in the inverter before it failed.

If the inverter has failed you will get codes and warning lights. With the right codes Toyota will replace it free.

 

You may want to recheck the fill level and was Toyota ATF used? Some transmissions will run weird when you don't use OEM fluids. My brother changed the ATF on my mom's Honda and it started slipping. Changed it again with official Honda OEM ATF and the slip disappeared.

If that was the first time it was changed - Yes those plugs are jammed in there really tight from the factory. I have to use a 3-foot breaker bar; but once it's been broken loose and torqued back down to factory specifications - you should be able to unscrew it easily using a 10mm socket hex.

 

I took off the oil fill cap, looked inside, and found out that my engine is gunked up with oil sludge. I have looked online and found some solutions like sea foam, frequent oil changes, and using oil with additives. Jiffy lube changed my oil less than 5,000 miles ago. I replaced a bad pcv valve. I'm considering installing an oil catch can but I don't know where to get one of those. I'm not yet experienced enough on automotive technology, for me to take the engine apart and clean manually without risking making mistakes that lead to the very catastrophic failures that I'm trying to prevent. I plan to get a college degree to become a mechanic because I love fixing cars.

 

They are 25mm round plugs with a 10mm hex slot in the middle. I don't have car jacks and I don't have experience with jack safety yet.

 

Can you please clarify whether that "revving" without gaining speed happens only on steep hills, or happens everywhere?

 

That's not good. Means previous owner didn't change the oil on a regular basis and/or used cheap non-fully synthetic oil.
I wouldn't go more than 5K miles on a jiffy lube out change, because they use the cheapest bulk oil they can find on the market. That's also the reason they recommend 3K mile oil changes, because they know it's crappy oil. When I inherited my dad's Toyota SR5, it had Jiffy lube oil changes - dad was too old to do it himself and was cheap. When I drove it; I noticed low oil pressure when the engine was hot at a stop. The odometer showed 175K miles, so it was also due for an oil change. I did the oil change with Castrol full synthetic and OEM oil filter - problem went away. I suspect the cheap jiffy lube oil broke-down and lost viscosity when hot.

I wouldn't use Seafoam on a sludge filled engine and your also running the chance that the sludge is scabbing over an oil leak or oil burn issue. That's what that "motor honey" garbage does to an engine to temporary stop oil burn, so a car lot can sell the car. I would use about a quart of transmission fluid about 100 miles before an oil change. Then 0.5 quarts of transmission fluid and run it a thousand miles, then do another oil change. That will slowly strip the sludge out of the engine's interior. Transmission fluid has a lot more detergents in it than motor oil and doesn't strip the critical oil film on machined surfaces that prevents premature wear. Products like Seafoam are oil, sludge, and carbon deposit STRIPPERS. Makes sure you keep an eye on the oil level and keep changing the oil filters; because that sludge is going to clog it up. All oil filters has a built-in bypass valve, that will open when clogged - but then your filter isn't doing it's job..... If your oil lamp comes ON; you need to pull over and shut-OFF the motor immediately or your going to damage it - well damage it more than what has already occurred.

Good Luck.......