2010 P0302 Cyl 2 Misfire & White Smoke

Thank you

 

UPDATE #5
I haven't had to drive much lately but am still looking for the root of my problem. Today I pulled spark plug #2 and inspected it, compared against #3. See the photos. Neither smelled of gasoline, just wonderful oil seasonings. #2 looks "dirtier" to me, but any visual feedback from y'all is appreciated. Still experiencing the same Misfire (hesitant startup) & code 0302. I've noticed that misfiring doesn't happen if I let the car sit for a day or two. But after I start & drive it for any length of time, stop at the store, say, and 20 minutes later go again, that's when it misfires and sounds all clunky until it warms up.

Plugs were changed 19k ago. I may just change them while I have the wiper assy. off.... And when my tank gets down to 1/2 I'll put in the Techron. If these don't help I'm gonna bite the bullet and head to the shop. I just don't think I'd have the know-how to take the diagnostics any further.

 

Thanks. I don't know how to clean EGR circuit as some things are just beyond me, and I'm running low on patience to do it. But thanks for the great tip and I'll mention it when I bring it to the shop.

 

Yes, last week I switched coils 2 and 3 and cleared the code, and P0302 came back again a couple days later. In other words, misfire stayed on Cyl 2. Stupid me didn't think yesterday to switch spark plug 2 and 3 when I had them out. I will do it tonight or tomorrow.

Today was the worst misfire day. Although it didn't misfire the first time I started it up cold, and the Check-Engine-Light actually went OFF after a 30 mile drive (much of it uphill), almost every other time I started it up, the rattles and shakes were pretty bad. Even hesitated a couple of times while on the highway, as the ICE kicked in and the check-engine light blinked for 10 seconds (bad!).

I'm fearing the worst at the moment. Mainly because last week I had filled coolant up to the "seam" in the overflow, and today before starting up I saw that it has dipped below the "Low" line. It was a little higher after a 30 mile drive, but not much. (Level stayed the same after the return 30-mile drive also). So while I was hoping this was just a fuel injector issue, I'm afraid it is a blown head gasket, or worse. Which doesn't make sense because I swear I smelled raw fuel in the exhaust last week. Could a bad spark plug or injector cause coolant level to dip? I have not gotten any overheating warnings. Or maybe coolant loss is not related to 0302... who knows?

 

It's just strange that the exhaust still smells like raw gasoline (I just cranked her up and yep, hesitation and yep, raw gas) and not Antifreeze/Coolant.

Putting a new spark plug in #2 tomorrow to see what happens.

 

TODAY:
Filled coolant to the middle of the F in "FULL"
Replaced Spark Plug #2, cleared code P0302.
We'll see what happens. If code comes back and coolant goes down, I'm taking it in for a proper diagnosis.

 

UPDATE:

After replacing Spark Plug #2 with new, I had 1 wonderful day of driving without any misfires or choking or anything, & ICE kicked on as smooth as I can ever remember. But yesterday wasn't so good. Shaky noisy misfiring cold start was back, as well as a few misfires during the drive. Today was better, though not perfect. It seems random. No codes thrown yet since I change plug #2, but it's only a matter of time b/c I can hear the misfire.

Still not overheating, and my MPG has remained over 50 since all this trouble started.

Best I can tell I'm losing about 1-2 cm of coolant per day - referring to the reservoir level (probably translates to 1/8 to 1/4 qt?). This varies a bit based on how much I drive, how far, probably how long it sits between drives, etc.

At my last oil change I was told I was burning oil, but I have checked the level every so often since then and it's fine. And the oil looks healthy. So does Rad fluid in the reservoir. I can see oil on engine components down below, but it could've been there forever, who knows. Also I've had this before on a Lexus and it was the symptom of a leaking Valve Cover Gasket. Could that be the issue this time too? I don't know.

Taking it in this week for a proper diagnosis.

 

Went by my long-time mechanic today. Described all the symptoms and my troubleshooting process. Without even looking at my car, without hesitation both owners said it's a blown Head Gasket -- and that they see this a lot on 3rd gen Prius. Actually, one of the shop owners' Prius (he has several) was up on the riser having the exact same thing done while I was there. They said the blown HG happens on this car because the Water Pump fails first, something about the WP not having a gauge on it. Here's the damage:

$1250: Head Gasket replacement, all seals etc including new Valve Cover gasket, Machining heads if warped (3rd party)
$450: Water Pump replace (AISIN brand)
($250: Valve job, if needed - 3rd party)

I did ask if Bar's Head Gasket Fix or any other sealer would help -- he said no, because the Prius engine doesn't run full time, and that it would clog up my radiator. This is similar to what a lot of reviews say. If anyone has feedback or experience with any HG Sealer, shoot!

Of course they recommend I spend the money... they're a business. But I trust their judgment -- mainly because they service a ton of Priuses, I think a whole fleet of Taxis -- I see Prius taxis in there every time I go. And the shop owner owns several Priuses himself. I could sell this car (171k) with a bad engine for maybe $3k-4k, but I can't buy much with that $. So I think I'm going to just bite the missile on this one.

That said, I want to hear what y'all would do here. Worth the $1700-2000 to fix?

 

Thanks. I don't have control over the process once they open it up. Water pump price includes labor, that's probably why it's 2x what you paid. I'm not doing any of this myself, for many reasons. I'll ask if they can clean the egr etc while it's apart.

In any case, I'm leaving town this week for a few weeks, it'll have to wait until I get back.

Not a fun cost to incur, but that's what I get for buying a higher-mileage car.

 

Thanks y'all. Advice taken. I'm gonna have it done in a couple weeks (going on vacation). Gonna use a 10-month 0% cash advance offer from my credit card company for this. I technically have the cash now, but I don't wanna drain the bank tank at the moment. I will post an update after the repair is done, etc etc.