Cylinder Misfires

How many miles on the car?

It could be a bad head gasket. It is very common for this engine if it is over 140k miles.

Check the level of the engine coolant.

When the head gasket goes bad, engine coolant will seep into cylinder 1 or 2 and cause misfires, especially during cold start-up. The engine coolant level in the plastic tank will go down very slowly at first.

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A severe metal to metal sound at startup that goes away for the rest of the day and sometimes days or weeks is early hg fail. A replacement hg may work but often fails again. A rebuilt engine is the best bet.

At this stage a high quality dual camera borescope used with coolant pressure can be diagnostic under experienced eyes. Steam cleaned piston compared to others and sometimes a coolant seep can be seen.

Or you can throw a thousand or two into plugs, coils, egrs and feel good for a few weeks. You will get suggestions how to throw away dollars.

 

Dibs on 150K.

 

Practically nothing but a hg. Shutter then run ok.

 

Sound like the early stages of a failing head gasket.

Did you check the engine coolant level?

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Time for boroscope inspection of cylinders (with cooling system pressurized) and/or leak-down test.

EGR system and intake manifold EGR passages never cleaned?

 

Same thing happened to me (cylinders misfires) Replaced head gasket. Strange thing about this car doesn't use a drop of oil. Never has 3 months owned it. Guess cylinders must still be in great shape with around 250k miles. Read on this board from Mr. Leisk and others that prius prone to clogging up exhaust manifold affecting couple cylinders. Told to clean it out every 60 k miles by mechanic for 200 dollars. Save another head gasket replacement.

 

100k’s about the latest you want to delay that. Sooner is better. There’s a correlation between clogged EGR and blown head gasket.

 

Block test tests for carbon monoxide in coolant, which is not what typically happens, at least not first. The tests I mentioned in post 8 are more conclusive. In particular the boroscope inspection, which should be be with coolant system pressurized, looking for coolant leaks into cylinder.

Having dealerships diagnose and deal with clogged EGR can be very expensive and fruitless; they will only replace parts, won’t “stoop” to cleaning, and the parts (EGR cooler/valve/pipe and intake manifold) are about a grand USD, and then there’s the labour. If there’s anyway to DIY I’d go that route.

 

Keep looking for an independent mechanic. Dealerships are a very expensive choice for old cars.

Head gaskets are head gaskets. The methods to diagnose and replace them are ridiculously similar whether it's a 1972 Dodge or a 2014 Prius.

The EGR cleaning is a weirder situation. There are no official stats, Toyota has never acknowledged a problem nor made a recommendation either way.

 

Justin, due to your location, take a look at the links on Mendel's thread. Then from there, you will also find videos on how to do the complete job. I agree with everyone, regarding going to a dealer. Unfortunately, the dealer is only going to do what is necessary to stop the current problem and not fix it so it will run another 100k miles. There has to be someone in your area who is familiar with doing a head gasket job on an engine. And while they are doing the hard part, you could be cleaning the other parts that are clogged.

Where you are right now is going to take time to save money or spend a heck of a lot of money to try and save time. Choice is yours. Wish you the best!

 

It's pretty advanced for a newbie, and won't actually fix the current problem.

It might prevent it from happening again, but somebody's still going to have to deal with the head gasket.

 

When the dealer tells you it's $3500-$4000 for a head gasket (or much more for a rebuilt engine) turn around and leave. You can have a complete rebuilt engine shipped in from Southern California installed for that money. Almost any conventional mechanic can change the engine with a quality rebuild engine. You get a remanufactured head, new pistons and rings and a complete new seal set, including of course the head gasket. EGR cooler and intake must be cleaned. I usually recommend people replace the plastic intake which is hard to decarbonize and there are revised versions now.

 

I had a similar situation. Had the rough idle engine sputtering at startup. it happened .3 times. On the 3rd time, the check engine light came on.

took it to the dealership and read the dreaded code P0302, Cylinder 2 misfire.

Checked the coolant level and oil level.
All fluid levels are at normal levels.

Now this was my problem. I had to drive the car back from Arizona to California. I’ve done this trip many times and this was the first time I ever had this problem.

Since the engine light was solid and it was not blinking, the service advisor and I decided to reset the code and turn the engine light off. He said to monitor it and if it comes back on, then we can read the code again and then really get into the diagnostics.

for good measure, I added the Toyota OEM fuel injector cleaner and then filled up the tank for the drive home. I’m taking a big risk considering it could be the start of a head gasket failure. If it’s something to do with the coil packs, spark plugs, fuel injectors and/ or EGR then I guess that would be better than a head gasket problem.

I was ready for the worst case scenario, driving through the Arizona dessert at 112 degrees.

Drive the car for hundreds of miles and was planning to drop the car off at HybridPit in Orange County.

when we got to our halfway point in Fontana, Ca., we filled up at our favorite Costco Gas station. My car was was running like a champ, no engine lights so far.

at this point, I was confident to drive it all the way home. I cancelled my rental car reservations and went the rest of the 340 miles into Northern Cali.

made it back at 10:45 pm and the car was amazing! No engine lights and the car drove like nothing ever happened. All fluid levels are good and engine temp were all within operating range. Have 2 Scangauges monitoring the temps.

i know there’s a problem but until the light comes back on, hard to say what needs to be repaired.

here’s a picture of the Toyota oem fuel injector cleaner that I added before my trip back to Cali.



Been driving the car around town. All good.

If it wasn’t for the 3 rough idles at startup and the engine light coming on, you would never know anything was wrong with the car.

Driving the car back 700 miles from Arizona to California without any problems, makes me hopeful that my car problems is not as serious as initially thought. Or maybe not. Only time will tell and whenever the engine light comes back on.