missing under light throttle

Have you checked/cleaned the throttle body? Also, your PCV valve and hoses may be quite dirty as well.

A malfunctioning PCV valve can cause the symptoms you are having: PCV Valve Related Symptoms and Problems

 

Does this shudder every time you accelerate from a stop? Any engine whine noise when you brake to a stop?

 

Have you run a full-strength fuel system cleaner/solvent like Seafoam or B-12 Chemtool? Some fuel issues don't manifest under load because enough pressure compensates but under light load it's just enough to be a problem. Also, did you change the fuel filter (which should have probably been done by now).

 

I'm not sure using 4 rebuilt injectors is helping your cause. There's no way to know of those rebuilt ones are good. I would think you need to somehow get the dtc codes read, so you have an idea where the problem is coming from. It would take forever guessing at this.

 

EGR pipe from EGR to intake manifold and EGR port through intake manifold clogged with carbon. Mine (my 2010, not the '07) never threw a code either but cleaning as per this thread fixed. Not a bad job if you're DIY, just a little bit of digging to pull the intake manifold. I would at least check this out before you replace fuel filter!

Prius III engine knocking at high torque low RPM (solved) | PriusChat

 

The fuel filter is in the gas tank, along with the fuel pump.

If it were the fuel filter, you'd have a problem under heavier throttle as well. So we don't see your reasoning.

 

Curious......is this stutter/misfire more pronounced with "Light/Throttle" just after turning a L.H. corner?......mine displays these exact symptoms & I am convinced it is caused by I.M. condensate (yes, the same condensate associated with the "Knocking On Start/Up" issue) pooling in the I.M. & then being "Dumped" (centrifugal force from turning) into the airstream, with the resulting incombustible mixture.......wife & I each have a 2010 & both cars have this unique "Feature"....

 

sounds like very needed preventive maintenance on a high mileage prius.

 

Just buy a new valve. It's an inexpensive part.

 

Just to clarify my earlier post: You do need to pull the intake manifold and clean the EGR port which runs the length of it. You'll find this clogged, too, just as you have the EGR pipe and valve. It's a little time consuming as the air box and throttle body need to come off (couple coolant lines to the TB that can be pulled with minimal leakage) but can be done easily in an evening. Be sure to re-connect the large vacuum line to the underside of the manifold on re-install or you'll get the no-start code and need to tear the whole thing apart again. Guess how I know this?..

No guarantee this is your problem but I strongly suspect the car will run great once you've plowed through this. It does appear this is becoming a pretty common issue in high-mileage G3's.

 

They run about $10 or less?

 

I think xliderider may be confusing EGR valve with PCV valve. EGR looks to be ~$200 or more for oem new. PCV is `~$10.

As a bonus, changing the PCV is a snap with the intake manifold off.

 

Yeah, I guess I did. Thought they were same thing.

 

What is the process to clean the EGR valve and EGR port: is it sufficient to spray brake parts cleaner, or ??

Did you replace the various gaskets with new parts, or reuse the existing gaskets? Any concerns about vacuum leaks?

 

HOLY CRUD!

I had just recently purchased my 2010 five ATP with 140k miles. I have this same issue, took it into Toyota, they said misfire in Cylinder 4 and recommended spark plugs and fuel injection cleaning. I Replaced those expensive plugs myself and was looking to replace my fuel injector but couldn't figure out how to remove the rail without tearing out a bunch of other parts. I was hoping that wasn't the case so I came here to ask how the you remove the fuel rail and found this post. I have a question about your symptoms.

• Do you notice this issue immediately when the engine is cool? It only starts happening after the engine is warmed up for me, but happens exactly as you state. During low RPMs only.

Did you get the info for the teardown from TechInfo or some other place? I would love to have a good repair guide but from what I've read, most of the existing ones are terrible and not exact. I'm sure techinfo has it, but at $15 bucks a pop when I have issues can get expensive.

I'm in the US, reading through this and other threads linked in here it seems everyone that has this issue is driving a European model. Should there be any difference?

I really hope this is the issue, cause I'm definitely tired of it.

/\\/\\orlince