Misfiring or something else?

I Just cleaned the MAF sensor - the problem wasn't solved. I didn't get any codes related to the MAF sensor so this was more a shot in the dark.

 

So I let the car idle for like 40 minutes after a 25 minute trip yesterday, and while it was idling (i put the heat to max so it would keep the engine on) it was running pretty smoothly. This morning car was definitely running better, no CEL but pulling codes shows pending cylinder 3 misfire code. Not sure why this helped - unless it has to do with adjusting existing MAF learned settings so extra on time helps with that. Maybe I will disconnect 12v battery to help reset that. Regardless, I'm seeing cyl 3 code more than anything else & cyl 1 is #2 in frequency. When its really bad, cyl 2 also gets thrown in.

Maybe I'll try swapping coil 4 & 3 ( maybe this time it really is the coil) and once my friend lends me his spark plug socket, I'll pull the spark plugs to take better pictures.

I happen to have a smog inspection due very soon - and obviously this will be an issue with passing. On the torque app, the following 3 items say not ready: Evap, o2 and catalyst. If I remember correctly, 2 years ago, car passed even though these weren't ready... does anyone know for certain if these items just aren't read correctly by the torque app? What is interesting is that it says ready for misfire...

 

so I pulled coils # 3 & 4 to swap and see if problem moves from 3 to 4 and I found some oily yellow residue on #4 (even though #4 did not come up as misfire..). This oil looks like olive oil - even if the valve cover is leaking, I don't understand why the oil would be so yellow and "clean" looking. Can this be something other than oil?

 

So after swapping coil 3 & 4, it shows pending codes for cyl 1 & 3 (as before) in addition to the p0300 random misfire. Since it seems to not be coils nor the plugs (plugs are relatively new), then I guess I really need to do a good check on the fuel injectors - I did pour in a bottle of techron but over the past 15-20 miles didn't seem to fix the problem. I do understand that there is a possibility of a blown head gasket, or low compression in general, but I'm obviously not going to be spending the money to make those repairs on such a high mileage car. Best case scenario I would try a can of engine restore & a leak stop for the coolant to see how much longer I can keep it going. Its unfortunate that it's much less easy to get access to the injectors or I would have replaced them a while back...

 

Yup - I cleaned them really well before putting them back in - with q-tips & everything. The funny thing is that coil #3 was clean, and coil #4 was dirty. After swapping them, I continue to have issues with #3 while #4 is fine...so it does seem in this case that the coils haven't been affected by the liquid. I am also keeping in mind that the liquid may just be water that seeped in through the poorly sealed coil gasket thing (I believe there was a recall/tsb on this issue) as it doesn't smell like oil.

 

compression test was done about 6 months ago. I'm skeptical about results as I can't say the tester was good (see previous posts) and it did break on me, and dry compression test seemed to show even wear across cylinders... either way I'm trying to eliminate other potential issues before I go for that can of restore or leak seal - the misfire I had did go away (or at least were pretty minimal such that it didn't make the car jump) until last week - so its hard for me to understand why it would have gone away and then came back if it is something as serious as a compression/valve/head gasket issue unless that bottle of techron last time sufficiently cleaned the injectors and they need another cleaning (or a more robust cleaning this time).

I have also seen "white smoke" from the exhaust, but it has only been when the car was cold in the morning, so I chalked it up to just condensation being burned off like with all cars in the cold. In the past week I've seen it too, but again, if its not firing on some cylinders, my understanding is that the excess fuel is being burned off and this is to be expected (and it is still quite cold here so now 2 reasons for it...).

Either way, the one thing I never really checked was the fuel injectors... question is whether there is something that is easier to check first...

 

how do I check fuel pressure? is there any way to reliably do so via the obd torque app?

Here is some data logged by the app on my last trip:
I do wonder if there is anything useful in there...

 

So apparently there is somethign called Mode $06 testing in my torque app - and doing some quick reading it seems that it will give me more granular data about what is wrong - I'm going to look into this more and hope that it assists in diagnosing the actual issue. this pdf I found in google may help decipher what each code means... https://attachments.priuschat.com/attachment-files/2017/07/128719_Diagnostic_Report_2017-07-05.pdf

 

so acc to this mode 6, its primarily cyl 3 that is misfiring - other cylinders misfire less than 1% as much = a few times per drive. This would seem to point a specific issue with #3. I will try swapping the spark plug (already swapped coil) and I guess I'll have to go for injector swap as well.

Previous tests did not seem to indicate that the #3 cyl had lower pressure then the others, so I'm trying to understand why only #3 would be causing most of the problems in the event the issue is not the spark plug or injector - is there anything else that would specifically cause a specific cylinder to misfire? I don't see any residue that makes me believe its the valve cover - could a head gasket failure at cylinder 3 be an issue?

 

Thanks! for $25 I can surely go for replacing the injectors. Let me know how well these work for you once you install them.

As an aside, I have another reason to suspect the injectors - a bit of googling says that a bad injector can cause a smell of gas - which I definitely do smell.

 

So I just pulled spark plug #3. it was covered in some sort of liquid - smelled liked gas/oil. I wiped it off and stuck it back in, then pulled back out and re-wiped and repeated like 10 times. Turned on car and seems to be running much better - took it around the block after letting it warm up like 10 min, and I'm not getting any misfires and car is much smoother (thought not 100% yet, still hear that kind of "something small being thrown around inside" noise). Is it possible that the whole problem is a leaking valve cover gasket?

some pictures:

Inside of cylinder before removing spark plug:


wet spark plug before wipe off:


spark plug after wipe off (but didn't yet wipe white ceramic)



Inside of cylinder with spark plug removed:


Car was spewing this grey smoke after which diminished as it warmed up:
https://photos.app.goo.gl/GA6mRMdO5KdfIakq1

 

So I was lucky enough to pass the smog inspection today. I haven't had misfires in over 80 miles (I believe that the emmissions readiness happened at around 75 miles after clearing the CEL). I also recently realized that the valve cover gasket only deals with oil leaks on the coils side (ceramic part) of the spark plug. If oil is on the interior (spark side) of the plug, does that mean its a head gasket?

 

Did your misfire go away after replacing injectors?