2014 Prius Plug-in cylinder 1 misfire

Adam Guerra · Jun 12, 2020

Hey everyone, about 9 months ago I bought a used 2014 Prius Plug-in. Recently I started having misfires in the engine. I took it to the dealership and at the time it was only bad spark plugs that weren't changed by the previous owner. Now slightly later I have a check engine light and an even stronger misfire. Again I find myself at my local dealership and they are saying the problem is deeper than just spark plugs, or coil packs. They said it could be something in the cylinder or cylinder head. They are estimating my costs at least at 4 grand. Any ideas what the problem could be and what I could be paying if I took it somewhere else? Thank you.

QuantumFireball · Jun 15, 2020

Blocked EGR system can lead to serious knocking/pinking, and head gasket failure if it is left long enough.

Rmay635703 · Jun 15, 2020

Mendel Leisk said: ↑

With the EGR circuit and intake manifold, the more you can DIY the better.

It's labour intensive, and if you work carefully, have the time, can cost you pretty much nothing, just the cost of cleaners. Both the EGR valve and cooler can be cleaned, no need to replace.

You will need a tool set, method to safely raise and support the front end of the car, and you may need to acquire a few more esoteric tools, specifically an E8 Torx socket (for EGR studs), and possibly an E6 Torx socket (for the throttle body studs. A 12mm ratcheting box wrench is nice too, for removal of the rear bolts holding the EGR cooler to exhaust manifold. You want to have decent torque wrenches too: 3/8" and 1/4" are optimal.

When I took the intake manifold off on ours, (albeit a lot earlier, around 70K kms) I just carefully removed all gaskets and reused. They all looked fine, like new.

Consider an oil catch can spliced into the PCV hose between the valve and intake manifold too.

A couple of threads worth reading right through:

EGR & Intake Manifold Clean Results | PriusChat

Oil Catch Can, Eliminate that knock! | PriusChat

Also, watch @NutzAboutBolts video on egr cleaning, intake manifold cleaning, oil catch can install:

Nutz About Bolts Prius Maintenance Videos | PriusChat

Comment on the videos: it's not really necessary to open coolant lines for any of these procedures.

When removing the throttle body (shown in the intake manifold cleaning video) you can leave the coolant lines attached, just separate the throttle body and shift it out of the way, say tie it with some twine.

With the EGR cleaning, you do need to disconnect coolant lines, but if you drain a couple of quarts of coolant (at the radiator drain petcock) at the outset, it'll drop the coolant level below the EGR system, so no coolant spills when the EGR components are removed. After reassembly just pour that drained coolant back into the reservoir.
Click to expand...

EGR system and cylinder misfiring | PriusChat

EGR & Intake Manifold Clean Results | PriusChat

Woodst0ck · Jun 25, 2020

Adam Guerra said: ↑

Hey everyone, about 9 months ago I bought a used 2014 Prius Plug-in. Recently I started having misfires in the engine. I took it to the dealership and at the time it was only bad spark plugs that weren't changed by the previous owner. Now slightly later I have a check engine light and an even stronger misfire. Again I find myself at my local dealership and they are saying the problem is deeper than just spark plugs, or coil packs. They said it could be something in the cylinder or cylinder head. They are estimating my costs at least at 4 grand. Any ideas what the problem could be and what I could be paying if I took it somewhere else? Thank you.
Click to expand...

I’m down 5k for the blown head gasket and then some. Get it fixed ASAP or it’s a hugeee repair.

bisco · Jun 25, 2020

Woodst0ck said: ↑

I’m down 5k for the blown head gasket and then some. Get it fixed ASAP or it’s a hugeee repair.
Click to expand...

how many miles on her when she blew?

bisco · Jun 25, 2020

Adam Guerra said: ↑

Hey everyone, about 9 months ago I bought a used 2014 Prius Plug-in. Recently I started having misfires in the engine. I took it to the dealership and at the time it was only bad spark plugs that weren't changed by the previous owner. Now slightly later I have a check engine light and an even stronger misfire. Again I find myself at my local dealership and they are saying the problem is deeper than just spark plugs, or coil packs. They said it could be something in the cylinder or cylinder head. They are estimating my costs at least at 4 grand. Any ideas what the problem could be and what I could be paying if I took it somewhere else? Thank you.
Click to expand...

how many miles on her?

2014 Prius Plug-in cylinder 1 misfire

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