Slightly shaking engine and rattling noise on acceleration

I gotta bump this, Since I'm still getting that hard rattling from the motor when I accelerate gently, I'm going to unplug the wire to the EGR when I leave for work today 3.12 and lets see what happens. If i accelerate hard the problem goes away, if I let go of the gas pedal the engine shuts off. It's just at light throttle. Highly annoying. And since I cleaned out the intake manifold and egr pipe to the intake around 130K I'm currently at 179K I hope it's not clogged again because I really don't feel like removing all that again especially the metal cowl under the windshield and wiper assembly. I'll update. Thanks

 

Check just the EGR pipe for build-up of carbon? That's relatively easy. With 50K miles since cleaning it might be building up again.

I notice a buzz, at low speeds, in a certain moderate acceleration zone. Push the gas a little harder, or less, and it goes away. Just sometimes. And I think can recall this practically back to new. I've only just got 80K km. I cleaned the EGR completely about 16 months back, around 70K.

Yeah, if that rattle is a regular thing, and it goes away with EGR disconnect, then it would seem to be the valve "fluttering"? Let us know how that goes.

Don't leave it disconnected though, as a "cure".

 

No I wont. leave it disconnected.
Yesterday I was at the gas station and before I filled up I put the car into maintenance mode and just revved the engine and I did notice some shimmering from the motor, but it does it when I'm actually driving. I went and unplugged the egr and the CEL came on, revved the motor and didn't notice a shimmering. I figured after I plugged it back and drove the car home the light would go away but it's still on. When I get home from work tomorrow I'll get go to my autozone and see what the code is.

 

It can take 5 or 6 start ups and the light will go off on it's own?

Yeah check that EGR pipe condition.

 

What about the OCC. I thought thats a major improve for all that nasty situatoon we all experience

 

OCC is a preventative measure. An efficient/effective OCC will trap a lot of the oil vapour being dumped into the intake manifold by the PCV hose. But I don't think that's the only reason the EGR is clogging, though it's likely a factor. And it obviously won't unclog an EGR that's already well along at clogging up.

I think the main culprit in the EGR clogging is Toyota's design: choices:

1. EGR inlet upstream of the CAT.
2. EGR passage too narrow.
3. Just not enough testing, since they all seem to be clogging.

With 4th gen one of the sales points is the EGR "improvements", which begs the question...

 

Update...I disconnected the plug to the EGR valve and the car ran beautifully. to & from work around 150 miles. So I need to get a new egr valve. How long can I drive without the EGR and what type of damage can I do without the EGR plugged in?

 

Engine will run hotter I think.

There's a diagnostic procedure (requires Techstream) in the attached (with suffix "testing").

Considering the "street" price for the valve is around $220, I would just check for clogging first, check the pipe condition.

EGR System for 2010 Toyota Prius | Toyota Parts

 

Thanks for the quick response, you're always on top of these problems. I'm going to drive 1 more day and park the car for a while. I'll use my other car. Then I'll figure this egr issue out in the meantime.

 

Dealer will change your egr valve for free if you have the right code. Got mine changed free but did not have any code

 

They changed it without question? I'm going to try that.

 

Yes they did . please get the right code i dont remember it. And tell them you got it from autozone scanner and now disapeared. Thats how i got mine changed for free

 

I don't understand what you mean tell them it disappeared. tell them what disappeared the code?
I have 180K miles, they might not even bother with me but i'm going to try this.

 

I'm sceptical: would they also change the EGR cooler, or thoroughly clean it? Ditto for the EGR passages in the intake manifold.

I get the sense the only way to do this right is DIY. And even if I was proved wrong, it's such a long shot.

Also, my 2 cents: the codes seem to come up when it's so far gone, the damage done. I was not gonna wait around for that.

 

Yeah now that I think about it, that's a little to good to be true, I wonder if his car was still under warranty and they didn't charge him. I'll call them.

 

I called Toyota at their 1-800 number, explained my issues, explained I did receive a warranty extension that expired in MARCH 2017, but at the time I did not have EGR issues. anyway they flat out told me THERE'S NOTHING WE CAN DO. Wow how helpful they are to a paying customer. I'm so effen mad right now.

 

Did also you unclog the EGR cooler (heat exchanger) at 130k?

 

nope. Because to get that cooler off is a major pain.

 

In a subsequent post you said:
"UPDATE UPDATE
I just unplugged the EGR power connector ....... driving around.....the problem as disappeared!!!!! Or nearly disappeared
What this mean lol"

I have what seems like the exact same problem on my 3rd gen. I would like to try this test before I replace all of the ignition coils/spark plugs/fuel injectors.

Maybe a stupid question but where is the EGR power connector and how involved is it to get at?

 

Apologies for reviving an old thread, but I answered my own question.

@ 2min13 second mark provided a clear visual and language on the EGR power connector.

Similar to OP, I unplugged the power cable and the horrible engine noise went away. So now I know I have to clean the EGR valve, or worse case scenario it's possibly a head gasket. This 3rd gen car has only 100k though so hopefully it's not the later.

This thread was great, saved me from jumping straight to coils/plugs/injectors first. Thanks guys.