Misfire continues after I change the ignition coils and spark plugs

Your right it is a misfire. But plug, coil and injector misfires don't go away after the engine starts. It is 95% a far too common head gasket leak on 2010-14 Prius engines. Especially if it sounds like this:

 

Wow. I learn something new every day. NOT.

ANY kind of mis-fire can go away after the engine starts.......until it gets bad enough.

I would do some techron in the gas next.....and or actually check the injectors.

 

Have you checked your coolant level?
From P0300 Code - Meaning, Causes, Symptoms (& How to Fix it)
in the first paragraph of the description
there is a misfire in cylinders 1 and 3

Did the same codes come back after you changes the plugs and coil packs?

If it's the head gasket you want to study how to deal with that SOONER than later.

 

I would have it checked out with a borescope and possibly a leakdown test to confirm. Ideally at an independent shop that is capable of head gasket and or engine repair work. The work is the same as any Toyota four cylinder but experience in hybrids would be a plus. You don't want a lower cost head gasket issue to grow into an engine if it is not already engine time.

 

This never gets old. When you're getting P030X codes, in a third gen Prius, 99 times out of a 100 it's the head gasket. Especially if it's of a "certain age", say 100K~200K miles. START with a leak-down test.

What is the miles btw. And has the full EGR circuit been cleaned? More info in my signature.

 

Your screwed................... new engine if it's been using any oil but I changed HG and didn't do anything to the head.

Still running.

 

I saw a commercial for Street Outlaws while searching the guide for something else to watch while the commercials were on, I heard them say at the end "Your Royally Screwed" and I thought of this thread.

I hope we didn't loose ya @denizbaba and ya can find a shop to fixya up.

 

A new video on exactly your problem on a 2012 Prius v.

 

Thank you so much for displaying this video. Hi-I have a 2012 Prius V-bought it about two years ago-drive a lot have like 231 on it now. Last week heard this godawful sound… went to this private shop and he wasn’t around… went to Monro-which they always have a space opened to check out the car… well guy did scan with a little handheld scan… said cylinder one misfiring… had plugs with me and got them changed with one ignition coil… still had hesitation and weird sound… went back and guy said just drive it around for a couple of days-and come back if there is a problem… said was likely unburnt fuel… well ended up up going to Prius chats and saw this post on there that mentioned and described blown head gasket. Was able to take it next morning to shop that sold this Prius to the guy I bought car from and they just work on Priuses. They did head gasket and water pump with oil change for 2500… they checked egr said looked clean… there mechanic was going on vacation on Monday and figured can maybe get that cleaned thoroughly when they or another place may have more time…took it in Thursday at 11 am and got car back on Saturday at 1130am. didnt want to tell them to do it when they said looked “pretty good.” This YouTube video was priceless -I likely would have driven it until head warped and would have needed a new engine… just wanted to say thank you as listening to the engine was beyond helpful in describing and showing exact symptoms Prius has when head gasket is blown… thanks to Critic as well as saw many of his posts on here describing symptoms of blown head gasket.

 

There goes any gas savings. Get ready for the brakes to fail.

 

Good deal. Even some of the oldtimers here sometimes need schooling as well.

 

And some of the newcomers need to go back to 5th grade English and learn about sentences and punctuation.
Ignore mode ON.

 

Assuming you have 231,000 miles on it: I'd suspect they never looked at it.

If you don't want another blown head gasket, clean the EGR components, including intake manifold, soon. See first two links in my signature.

 

Great advice...
My advice get rid of it.

 

I am curious… would actually changing the egr valve be essential before cleaning out the components? I do think the egr valve was replaced about 75000 miles ago? I took the mechanics at their word regarding the egr components… I didn’t see any benefit from them not recommending cleaning the system since they had everything apart anyway to replace the head gasket. I have driven about 1500 miles since the fix and car is driving well. I can appreciate the sentiment about “getting rid of it.” However, Vehicle prices are beyond brutal now. I purchased the car outright for 6500 about 2 years ago and this is the first major problem driving about 65000 miles… I had a battery replacement service Greentec batteries in Maryland check out my hybrid battery and they said everything looks good and didn’t recommend to replace it. I also think many vehicles above 200 thousand miles eventually have major problems… I am hoping-and I know hope can be the cousin of delusion-but am hoping can have it get to 300 thousand miles and go from there. The brake actuator system going bad could be a tipping point unless could get it fixed for 1500 as opposed to three thousand dollars.

 

A head gasket job is far less than a new or rebuilt engine on these cars with their bad rings and resulting carbon buildup. So making 300k might be a push. But I would change the oil every 5k religiously and clean what you can out of the intake and egr every 50k.

The problem is the head and combustion chamber which is next to impossible to clean especially on the engine. Bottom line- if you see a financial window to move to a gen4 car go for it. The 2012 will sell quickly to a new fanboy.

 

Replacing the EGR valve may be warranted, if it’s internally damaged. There’s a “ski ramp and stop” gizmo that has been getting degraded, perhaps as a consequence of the carbon clogging, not sure. @ChapmanF has a pic and more info.

The “bad” rings are not defective; they have less outward spring, by design, presumably to reduce friction, improve mpg.

Either due to those rings or clogging of the oil passages within the pistons, oil consumption can get going, and get progressively worse.

Toyota issued a technical service bulletin regarding excessive oil consumption, and their fix involved replacement rings and pistons, with revised parts. These revised parts were also put into the new engines, commencing partway through model year 2014.

that said, I don’t think the carbon clogging of the EGR system (and the EGR passages in the intake manifold) are a consequence of oil consumption.

One “test subject” is our 2010; to date it has no discernible oil consumption, but it did have carbon build up in the EGR. Also, I doubt 2015 model year Prius (with revised pistons and rings) are exempt, not carbon clogging their EGR’s.

I think the EGR carbon clogging is a natural consequence of the design shortcomings, as evidenced by the changes they made with 4th gen (2016 model year onward).

 

Carbon comes from the oil