Oily Spark Plug On A 4th Gen and Misfires On Cyl 6... HELP!!!!

i have been having some rough cold startups on my truck lately as if the engine is hesistant on startup but once started it runs pretty fine until about a week ago i had the engine light, vsc trac and vsc off light come on,
so perplexed about what the issue is, i take it over my friends house (toyota technician) to run a scan on it, so the scan reads the Cylinder number 6 misfires on startup and that the warning lights come on 9 seconds after startup and in another problem...

i also noticed that my engine has been fluctuating temperature rapidly only sometimes, most the time it would be steady in the middle so we checked that also and it was down 3/4 of a gallon! where did this fluid go??? i havent noticed a external leak, i just hoe its not internal

so my friend says that maybe the two are related, maybe there is a internal leak of the coolant and it is causing the misfires on cyl 6, so he suggest to pull the plug when the engine is cold and check to see if there is moisture, so this afternoon when i get home from work, i let the truck cool with the hood up for about 3 hours and i pull the plug and what i find is that the tip and the lower half of the threaded area appears to be okay but the upper portion of the threaded area is kinda oily along with the lower portion of the ceramic, so it seems to me like there is some type of leak on the top part of the plug maybe a gasket from the valve cover to the head??? so i inspected the cylindrical tube that connects to the spark plug and it all seemed to be dry, so i replaced the spark plug and put everything back together and i started the truck and it was a smooth startup and i revved the engine and held it steady at several rpm levels and it seemed fine. then i put in reverse with my foot still on the brake and still fine but at the moment i started to move backwards the vsc trac and vsc off lights came on????

so at first i thought maybe under load it misfires but that didnt make sense since i was running the engine at a high rpm and still no lights-


does anyone have any suggestions and ideas what maybe the problem and what maybe the fix?!?!?!


thanks!!

no one?

the_josh said:

i have been having some rough cold startups on my truck lately as if the engine is hesistant on startup but once started it runs pretty fine until about a week ago i had the engine light, vsc trac and vsc off light come on,
so perplexed about what the issue is, i take it over my friends house (toyota technician) to run a scan on it, so the scan reads the Cylinder number 6 misfires on startup and that the warning lights come on 9 seconds after startup and in another problem...

i also noticed that my engine has been fluctuating temperature rapidly only sometimes, most the time it would be steady in the middle so we checked that also and it was down 3/4 of a gallon! where did this fluid go??? i havent noticed a external leak, i just hoe its not internal

so my friend says that maybe the two are related, maybe there is a internal leak of the coolant and it is causing the misfires on cyl 6, so he suggest to pull the plug when the engine is cold and check to see if there is moisture, so this afternoon when i get home from work, i let the truck cool with the hood up for about 3 hours and i pull the plug and what i find is that the tip and the lower half of the threaded area appears to be okay but the upper portion of the threaded area is kinda oily along with the lower portion of the ceramic, so it seems to me like there is some type of leak on the top part of the plug maybe a gasket from the valve cover to the head??? so i inspected the cylindrical tube that connects to the spark plug and it all seemed to be dry, so i replaced the spark plug and put everything back together and i started the truck and it was a smooth startup and i revved the engine and held it steady at several rpm levels and it seemed fine. then i put in reverse with my foot still on the brake and still fine but at the moment i started to move backwards the vsc trac and vsc off lights came on????

so at first i thought maybe under load it misfires but that didnt make sense since i was running the engine at a high rpm and still no lights-


does anyone have any suggestions and ideas what maybe the problem and what maybe the fix?!?!?!


thanks!!

Click to expand...

Does your engine oil look like a milkshake? You might have a bad coil, try moving the coil from cylinder #6 to another cylinder and see if the problem follows it.

Lookup Blackstone Laboatories on the internet (google) and request an oil analysis sample kit. Follow the directions and take a sample of your engine oil and send it in. It will cost you $22 for them to check it. If you have an internal coolant leak it will show up on the report.

Then have your friend clear the codes and swap one of the other cyl coils to that one and put a new spark plug in where the oily one was. See if the code follows the suspected coil. If it does replace the coil.

Please post back and let us know what it is.

did some more work on the truck today and all the signs are pointing to either a blown head gasket or a cracked head, wont know till we start to take it apart which will probably happen in a couple weeks til then im not gonna drive it

the key signs that make up think that was the smell of the coolant, the loss of coolant when we pressurize the system without the truck running, and when the truck is running we stuck our finger inside the radiator and felt the water and there was this contant bubbling (not a burping of the system but a steady bubbling) and these air bubbles were of a higher temp than the water which has to mean its combustion air that is seeping through the cooling system

so this week my buddy is going to pick up a special chemical from toyota that you add to the coolant and it will change color if it has contact with any combustion gasses and that will pretty much confirm that theory ;(

What did you find? My 04 V6 has that same stumbling when it first starts. Changed plugs and didn't notice anything strange like moisture. I do hear a bubbling for a couple of seconds when I start the truck but now everytime. It goes away pretty quick. I don't smell coolant, oil is fine, coolant isn't low. Swapped #6 coil pack with #4 and code followed the pack. changed pack and same problemcame back? CEL didn't stay on this morning. will check code when it does.

Sgt. Boz, did your problem go away? I had the exact same issue, misfire in cylinder 6, swapped the coils, but the problem came back on cylinder 6. It looks like I have a cracked head.

Is anyone else seeing this problem with their V6 4Runners? I have an '04 with 140k miles.

cbradley said:

Sgt. Boz, did your problem go away? I had the exact same issue, misfire in cylinder 6, swapped the coils, but the problem came back on cylinder 6. It looks like I have a cracked head.

Is anyone else seeing this problem with their V6 4Runners? I have an '04 with 140k miles.

Click to expand...

take off your radiator cap and smell the coolant? Does it smell like Coolant or hydrocarbons? (exhaust)

and the surefire test is to do a pressure leak down test on all the cylinders for comparison, you said cyl 6 is the issue? So pressurize that cylinder at TDC and see if it holds pressure? And if not where the the air going? I'm my case cyl 6 was losing pressure and bubbling in the radiator which meant it was a warped head or blown head gasket, I'm not sure which, the engine is still sitting in my garage