2013 Prius Gen 3: Fuel injectors or EGR?

Folks, My daughter brought me her 2013 Prius with that dreaded rock, rattle, and roll noise. Being retired has its disadvantages. . Guy at Toyota said it could be a head gasket. Sounded more like bad fuel to me. I replaced the plugs. I figured 160K on them was enough. That fixed the problem to around 95%. I could hand it back and she’d probably not notice. But it still hints at going there on take off and up to 10 mph. I don’t really want to take the wipers etc off again, but I guess I will if needed. Don’t mean to sound lazy, but I’m old and tired.

Do you think this sounds like a fuel injector problem or EGR issue? If it sounds like EGR issue I’ll take the whole thing apart (cooler, valve, pipe, intake) and then do injectors. Not sure why anyone would just do part of EGR. Doesn’t make sense to me.

Anyway, thanks in advance.

 

‘Thank you. Not being a mechanic I did some steps out of order. Below is a summary of steps taken.

 

Update: I gave up on simple things and my sequence was out of order a bit. Here is a summary of what I did with results and what I plan to do. Please let me know if I’m going out of order or missing anything.

1. Added Heet.
- Not much change

2. Changed plugs
- Seemed to help. Ran a full day with no knocking, but still had hesitation when accelerating and felt like it wanted to knock. A day later drove 2 hours with no knocking. Two hours after that trip started it up and it started full blown knocking.

3. I finally read the codes…dope.
- codes included are P300, P0301, P0302, EGR

4. At this point I’ve only spent money on the spark plugs. I plan on paying attention to coolant level and ordered a block tester unit. If it’s a head gasket I will stop here because I won’t know if the head is warped etc. I don’t think it will be worth having someone replace it based on risk/reward. I don’t have the experience required to do that job.

5. If block tests ok, I will: 1. change out coils and test. 2. clean the injectors and test, and 3. Clean the EGR system, and test. Regardless of pass/fail on these tests I’ll do all of the steps because it has 170k and they most definitely need cleaning.

So, what do you think? Am I missing steps, out of order, bad assumptions? First time under a hood since the 70’s when you could crawl in there and make a bed.

 

Appreciate the advice. If this block tester works I’ll know which direction to head today. But actually, the knocking has diminished a lot since I received the car. It’s much less frequent and less intense. It’s also very random. It doesn’t always do it on cold starts. It’ll be fine for an entire day and then after driving for two hours and letting it set for awhile it will start doing it again. Block tester shouldn’t lie. If there is combustion gases there then it’s there. If not, it’s not. But honestly, in my gut, I’d say it’s a head gasket. I pray it’s not because I know my daughter can’t afford that.

Also, after I put the spark plugs in the engine light went off and it hasn’t come back on. I’ve tried to get it to come back on and it won’t.

I did not look at coolant level yesterday. Thanks for the tip. It is low. Leaning toward HG and awaiting kit. That sucks. So let me ask what is probably my first incredibly stupid question. Any chance pepper will block that leak, like it does radiators? Haven’t done that since 70’s, but figured I’d ask.

If I wasn’t living in a condo w/o a garage I’d be tempted to change that HG myself, but I’m no pro at that. It’d be a risky adventure considering timing set, torquing, etc. it’s a shame because parts are so cheap.

‘It’s definitely 7-11 gas and maintenance is lacking or nonexistent. . My daughter is a great person, but not attentive to these details. Thanks for your comment. I’ve learned a lot from you all. I’ve a bottle of Techron in my hand and that’s going in my Lexus now!

Not consistently, but it is low now. So, praying it’s not HG. But in reality it’s likely HG. Hints you guys are giving are headed down that road. No pun intended.

 

‘The heet I put in the gas tank to remove water. She first told me that it acting up on start up. My first guess was that water in the tank had settled to the bottom of tank and causing the problem. Seemed as though that helped a bit, but in the end that was not the problem apparently.

‘I stopped after spark plugs. Will do block test tonight or tomorrow before going forward. So, no I haven’t cleaned EGR. If it passes block test that will be one of next steps.

 

‘No, my ACTRON reader literally said “EGR”. Perhaps that’s not a code, but a monitor. Anyhow, those were the readings that I wrote down from the reader.

 

‘Mendel, are you saying that HG leak into cylinder 1 and/or 2 will not be detected as combustion gases in coolant when using the block test, or am I misinterpreting your statement.