2010 lx570 code po 304 UPDATE #2 (1 Viewer)

[TTO5]

Started getting this code for a couple days with no symptoms. I cleared it with my scan guage and drove the next day 100 miles. Started the truck later that day code is back, no flashing mil at this time. I cleared it and drove 100 miles back home. Today I used the truck this morning and no symptoms felt. Light did come back on after a couple short trips. Truck Sat in my driveway for a couple hours. Started it up and could feel the engine misfire along with flashing mil. Same code. Removed coil from cylinder 4 and moved it to cylinder 2 ( swapped cylinder 2 coil to cylinder 4) drove it a little and no codes. I then took a used coil that hasn't been on the truck for several years and put that in cylinder 4. Misfire and code came back. Put original number 4 coil back in and moved number 2 back to its original position. Drove it and no mil at this time. Wiggled wiring when running no issue found. Disconnect number 4 coil plug and mil back on but a different code relating to no signal which leads me to believe the wiring is OK. Maybe intermittent issue in number 4 coil thar didn't act up when put in cylinder 2? Not sure where to go from here. Truck has 235k on it and lovingly cared for

 

[Kinnada]

how old are the plugs?

 

[TTO5]

how old are the plugs?

115k so basically due. Wouldn't that just be a constant misfire?

 

[Kinnada]

115k so basically due. Wouldn't that just be a constant misfire?

could be random, i'd sure go there next in your troubleshooting program

 

[TTO5]

could be random, i'd sure go there next in your troubleshooting program

I started loosening the plug but it got tight after 3 or so turns. I got nervous and retightened the plug. Maybe I need to loosen it and spray some kroil down there

 

[grinchy]

I got some intermittent misfire codes due to a couple bad coils.

 

[TTO5]

Started up this morning after sitting overnight. Could feel a slight miss but it came out of it by the time I pulled away from my driveway. It didn't do it the whole way to work (20 miles). Weird thing is when I felt it this morning it did not turn the mil on.

 

[TTO5]

Got the plug out. Looks fouled?

 

[TimCFJ40]

For 115k plug that doesn't look too bad. I'd replace all 8 and see if your symptoms resolve.
I had a Misfire Cylinder 1 on a roadtrip 2 years ago at ~260k. Replaced the coil and it got better for ~1000 miles until it failed again. Replaced again and limped home. Replaced all 8 plugs and a new OEM coil in cyl 1 and it's been rock solid ever since, now over 282k.

 

[TTO5]

For 115k plug that doesn't look too bad. I'd replace all 8 and see if your symptoms resolve.
I had a Misfire Cylinder 1 on a roadtrip 2 years ago at ~260k. Replaced the coil and it got better for ~1000 miles until it failed again. Replaced again and limped home. Replaced all 8 plugs and a new OEM coil in cyl 1 and it's been rock solid ever since, now over 282k.

Fingers crossed

 

[TTO5]

Found 8 coils new in toyota oem boxes for $150 on ebay. I work at a Toyota dealer my cost is 80 bucks each. I ordered them. Hopefully they are legit

 

[32cls6speedmt]

Found 8 coils new in toyota oem boxes for $150 on ebay. I work at a Toyota dealer my cost is 80 bucks each. I ordered them. Hopefully they are legit

Make sure they are legit. Read the reviews for the seller especially the negative ones.

 

[grinchy]

I hate to say it, but I did a similar deal via ebay, and had two of the 8 failed within a year of replacement. They looked completely legit - toyota part numbered, visually identical, same weight to the OEM coils, and they worked great, for a while. One failed electronically (intermittent), the other cracked the coil side connector (was showing electrical issues too). After two failed I went ahead and threw the other 6 out, didn't even keep as spares. Just didn't trust them. I get way out in the boonies occasionally and messing about with failed coils is not a great idea when it's a long tow (or impossible tow) to the nearest relief.

I replaced these with 2 OEM coils (used for troubleshooting, then kept them), and 6 Denso coils from Rock Auto, which have the serial number ground off, but are otherwise identical to the OEM (OEM Supplier is Denso). I feel pretty confident these 8 will be good for another 240k miles. I have one 'generic' coil I bought in a pinch from the local auto store that I carry in the drawer now. It works fine, but I don't trust it long term. Will be fine to get back home if one of the Denso or OEM coils go early.

Not included here is the 6-8 weeks of me chasing various ignition codes while trying to determine what the core issue was . . .

 

[TTO5]

I just canceled the ebay ones and ordered 8 of the denso coils.

 

[TTO5]

Ok I installed 1 new sensor coil last night along with a new spark plug. I don't feel misfire and mil stayed off. As of last night the scanguage showed no pending codes but this morning it shows pending misfire cylinder 4 again. No symptoms felt. Anyone know if the scan guage 2 is not able to clear pending codes or is it actually a true indicator that something is still wrong?

 

[TTO5]

Wondering if it's fixed. Nervous about the pending code still being stored. Looks like misfire test ran and passed?

 

[TTO5]

P0304 still in pending. I can feel the misfire right after start up. Lasts for a couple seconds. Truck Sat for 8 hours. Injector leaking?

 

[TTO5]

Ok truck Sat 3 hours. Started it up feel misfire mil came on flashing. Let it run about 20 seconds. Turned engine off, restarted truck. No misfire felt, mil on solid. Code po304
Wtf?

 

[TTO5]

Ok so I pulled cylinder 4 spark plug out (had about 100 miles on it). Found wetness on porcelain and a black patch of something. Put my endoscope down the spark plug hole and was greeted with a very wet piston top and cylinder walls. I'm leaning towards the wetness being oil instead of coolant. For comparison I pulled the cylinder 2 spark plug out and it looked as expected for 115k mile spark plug with none of the blackness I found on the cylinder 4 plug (when I pulled the 115k mile plug from cylinder 4 it was very black with no light coloring on the porcelain. I scoped cylinder 2 and it's almost completely dry maybe a couple spots of liquid (assuming oil). The only codes I ever got were p0304 for cylinder 4. Only happens after it sits a few hours. No idea what to do. I found a 45k mile engine on ebay for 6k. Might go this route? I don't want to pay bunch in teardown to find the issue only to lead to engine replacement. Thoughts. Suggestions? First 2 pics are cylinder 4 plug with 100 miles on it. Followed by cylinder 4, cylinder 2 spark plug with 115k then picture of cylinder 2

 

[marques]

Maybe a leaking injector? Getting them professionally cleaned will be a lot simpler/cheaper than swapping the engine.