2010 prius

Clogged egr circuit. Hopefully, the head gasket is still intact.

 

See the @NutzAboutBolts video on YouTube

 

From what you wrote and observed, it’s not possible to be 100% certain of the cause. For instance, it may be that your spark plugs are finally failing after 200,000 miles. But it could be that oily deposits are causing misfires, and when you replace the plugs, the misfires will stop only until the oily deposits come back. You can look at the plugs and the intake to get some ideas.

Basically, you’ve got two choices:

1) Keep driving the car until it breaks.

2) Stop driving the car until you fix the root cause of the problem.

I recommend #2, but it’s going to take you some work. Personally, I’d pull out the EGR valve and cooler, intake manifold and spark plugs. Just do it all. It’s all basic engine work; nothing hybrid-specific about any of it. But if you’ve never worked on a Prius or a recent-model engine, it will take you two weekends and your car won’t be running. You’ll need to be very organized as you remove each bolt, because you’re new to it.

If you want to tackle this, we can help you, maybe some of us can FaceTime with you to help answer questions as you’re doing it.

You only need basic tools: Screwdrivers, a 3/8” metric ratchet set, a spark plug socket and a ratcheting wrench (not socket, a wrench) in 10-13mm (I forget) for removing the EGR cooler. A small drain bucket. I don’t think you need to jack the car at all.

Parts cost is next to nothing: Set of spark plugs, about $50. Some gaskets, about $25. Cleaning fluids, shop towels, brushes.

Last thing: If you’re losing engine coolant (plastic jug with pink fluid on passenger side), and especially if you’re getting white exhaust smoke, you’ve got a much bigger problem. (You’re past Choice One, above).

 

For the p0103 code, that points to mass air flow sensor. Try cleaning it with MAF Sensor Cleaner (CRC for one makes it). Don't use anything else. You basically give it short blasts. You unclip a connector, and remove a screw or two, to lift the MAF sensor off. It's located here:

I think the code associated with that is P0301? Cylinder one misfire, with 220K miles, is almost invariably head gasket failure. Is the engine coolant level stable in the reservoir, or no?

 

And you're not having to top it up?

FWIW, clogged egr and blown head gasket around cylinder #1 seem to go hand-in-hand. The EGR feeds into intake manifold at other end, cylinder #4, which may be a factor.

That alone is troubling. Lots of reports of blown head gaskets here with anywhere past 140K miles. And usually the EGR and intake manifold have never been cleaned.

I would concentrate on the head gasket first. Leak down test is good to figure out if and how it's leaking. The usual is coolant into cylinder 1, maybe 2 as well.

If you do resolve the head gasket, complete egr and intake manifold should be next.

 

Where whom did you buy from?

 

well done!

 

The EGR pipe is just tip of the iceberg.

 

Clean the entire egr circuit & added OCC

 

Considering the code, the miles, the lack of cleaning: leak down test.