Misfires, you most likely overheated your Prius

This applies to all Prius most likely unless your car has a mechanical water pump.
Too bad I can not post for other generation owners to read.
Anyway my 2013 going on 450 thousand miles, has had its share of issues, and after reading what others claim the cause of misfires I have wasted time thinking these ideas would cure the misfires.
What I have learned, the misfires are most likely a head gasket that is leaking coolant into the cylinder and causing the misfire.
Yes you over heated your Prius and didn't know it.
I am an industrial maintenance mechanic also electrician, welder, fabricator, you name it, I fix pretty much anything.
This is the second engine on my Prius, the first one, as you guessed it overheated and throw a rod sliced the front, the back, and took out the AC compressor on the way.
It lasted 285k, so not bad, but If I would have known what I know today, I would have the same engine.
I new my car overheated and I didn't know when or where, I also figured out that it had overheated before but not too bad, only bad enough to give me misfires after sitting a couple of days.
The last time it really overheated, again without any warning, thanks Toyota, when I started the car the next day, it had so much coolant in the cylinder that it bent the rod that failed, I new the motor was pretty much gone, I had to leave for work, and the only way to keep it running and not get misfires was to drive in engine brake so the engine stayed running continually, if the engine stopped and ran in electric as soon as it started it would misfire.
After going around with some crook to get my replacement, this was another nightmare, I installed and Ultraguage, this is what has saved my current engine and would have saved my old engine.
These cars come with an electric water pump, that can and will overheat in a matter of seconds, when this happens, it just shuts off without any warning, well I'm sure you can figure out the result and how fast your engine will overheat because there is no coolant circulating, the pump will not stay off long most of the time, depending on the load, for me I and my wife experienced this 20 to 50 times, thanks to Ultragauge I still don't have any misfires to date.
I'm not sure if any of you have heard of a thermal overload, when an electric motor gets hot it just turns off and self resets once it cools down a little.
This is the Prius water pump.
Call it what you like, I am not here to promote Ultragauge in any way, I have had and still have a Scanguage 2 that I don't use, the Ultraguage has alarms, the the kind that most car manufactures put on the cars, you know the smoke signals coming from under the hood, you get this alarm your done.
Do yourself a favor, buy an Ultragauge and install it on your Prius, get it from the manufacturers website, they are cheaper than buying on ebay, the MX model you can add things that the regular one doesn't have, really the only thing I was able to add that is not on Ultraguage Plus was SOC, State of charge, this is for the hybrid battery.
If you have misfires, replace your head gasket
90 dollars Ultraguage can save you from headaches and spending money on what is a great car.

 

if you get an Ultraguage and your pump shuts off your you have less than a minute to let off the gas and pull over, yoiur car will go above 250 degrees in seconds, this is ok as long as you let off and pull over, the head gasket will hold fine, I have been there multiple times, but if you don't have a warning of any kind except for the smoke signals from under hood, I dont think the head gasket can last a minute without coolant circulating
As for the EGR keeping engine cool, I don't buy it, and I'm definitely not concerned with mine, if it gets completely clogged I should get a code and will not be able to pass smog, in this case I will change it out with the spare I have.
Buy an Ultraguage, you will not regret it
Misfire I have experienced on this car is mainly on startup, the spark plug is wet and when the coil provides power to the spark plug to fire, the spark is not able to jump to the electrode I assume it is shorted out, after a few tried eventually it will get a spark, after the first spark the cylinder temperature rises to the point of flashing off the liquid in the cylinder and you will no longer have a misfire as long as there is no liquid in there.
A single misfire will make the engine shake because it is out of balance when a cylinder fails to fire, multiple misfires most likely more than 1 cylinder is not firing, a bad head gasket will put liquid into 2 cylinders most likely.

 

Here is a mixture of my first engine

 

Oops, can someone delete these duplicate posts, I don't see an option

 

rjparker, does that gauge have settable alarm?

 

View attachment 249586 Here is a picture of my first engine

 

Cars have had temperature gauges probably before I was born, and they don't work because by the time the smoke signals come from under the hood its too late
Some say yes I have a temperature gauge so y car will not over heat, you have not experienced how fast the temperature goes up when your water pump isn't running, believe me 1 minutes you will blow the head gasket, no water pump running your car will reach 250 in seconds, less than 15 seconds under load.
Save you 100 dollars and enjoy your gauge, or dummy light, don't come crying when you have to pay the 1k because your car has the shakes.
I am not familiar with the other OBD reader, and yes i have apps on my phone for OBD, but I don't drive thousands of miles per year staring at my car temperature on my phone when I can be listening to music.
My post was to help people out, I have not changed my EGR for well over 200k, and have no plan to.