Toyota FJ Cruiser Forum banner

P0306 Misfire! What do I do?!?

19K views 22 replies 7 participants last post by  Cogen Man 
#1 ·
Two nights ago when I was driving home from work my engine started to shutter and lost almost all of its power. After a few seconds it went away, then came back, then went away. No check engines light.

Tonight on my way home it happened again. This time much worse. Felt like the entire front end was shaking and shuttering like crazy and there was all of the sudden no power. The check engine light and vsc, trac control, etc. all came on. I got off the freeway and pulled over. I turned it off and then back on and the lights went away and it ran smooth. Then when I was almost home it started again, and all the lights came on. So I stopped and restarted the engine. This time it ran smooth but the lights stayed on. I was able to scan gauge it and get P0306, cylinder 6 misfire.

First off, I do not know which cylinder #6 is?

About 1,000 miles ago I had the fuel injection service done at Toyota.

Over the weekend I washed the engine real good ( the same way I have many times in the past).

I have E3 spark plugs that have approx 18,000 miles on them.

Two weekends ago I cleaned the Throttle body and TBS.

I run premium fuel and drive like an old lady.

What do I do? Is this major?

I bought a spare plug so I have one here I can install. Is that the first step?
Did I jack something up when I cleaned the engine? Could water have gotten in somewhere?

What cylinder is #6?

Help! Thanks!!!!
 
See less See more
#2 · (Edited)
A code P0306 may mean that one or more of the following has happened:

Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). . Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. If it is something with the dealership injector cleaning 1K ago it should have started sooner I think. The engine cleaning was the most recent thing you did. Is that the culprit ?? Not sure which is #6 cylinder.
 
#3 ·
The last time I got this error code thrown on the '98 Taco it turned out to be a bad fuel injector.

Run it back to the dealer and get them to check their fuel injector cleaning job. Could be that they just ran some strong cleaner in your fuel and it may have dislodged some crud that clogged one of your injectors.

Funny that this started happening right after fuel injector service. I'd suspect that first. Also, check your spark plug wires; maybe the one on cylinder 6 (near the back of the engine on either side) may not have been put back on properly by the dealership, if they truly removed the injectors and cleaned them...
 
#4 ·
Toyota did a "F.I. flush." I understand that that means they hook the little bottle of cleaner up to the intake just after the throttle body and then run it into the system. I do not believe they removed the injectors and did anything to them directly.
 
#5 · (Edited)
Just curious. How many miles were on it when you had the injector cleaning done ? Yes they would have hooked up the cleaner bottle to the inlet connection to the fuel rail and run the stuff in. No need to remove the 6 injectors after the cleaning. This may have clogged up the spray pattern of the #6 injector enough to throw the code. I'd take it back and tell them to fix it.
 
#6 ·
I had an "injector cleaning" done on my previous truck around 60K I think. It wasn't running as smooth as it use too so I though a "quick cleaning" would fix it. It ran for about 2 days, then wouldn't run any more. All the "injector cleaning" had done was loosen up the crap and made it worse. $150 bucks down the drain. Had to have it towed to a Toyota dealer. I had them remove the injectors and clean them properly. $700 parts/labor. Ran like new though. I'll never do the injector cleaning again.
 
#8 ·
You could and they'd love ya. Ask them how much. As you can see in FJTTSE's post above it's a lot of loot. :mecry: Ask them to discount you the price you paid for the first F.I. cleaning. They'll give you the old :boohoo:
 
#9 ·
The problem is that I had the FI service done in San Diego at Toyota where my buddy works. I live in Orange County. I do not want to risk the 60+ mile drive to SD to take it to my buddy. I have to go to the local spot here and walk in and talk to whatever service guy I get stuck with!

Honestly I feel now like the FI "cleaning" did more damage than good and I really want to just replace all the injectors ( but AT LEAST #6)! So pissed that my buddy told me it really should be done!!!! He always talks me out of services saying don't waste my money so when he said I should do it I took his word it was worth the $100+

Any idea which one is #6?
 
#10 · (Edited)
Any idea which one is #6?

I believe #6 is back driver's side. Sorry awood. You've asked which one #6 was in a few posts and I didn't answer your question so here's the answer.
Firewall
5 6
3 4
1 2
Front of FJ
 
#12 ·
Engine cleaning was the culprit. This morning before taking to Toyota I wanted to check the spark plug from cylinder 6. I finally got coil wire harness off (of course I would have to jack up the hardest cylinder to get to) and removed the spark plug. Prior to removing the plug I tried to look down in there but really didn't get a great look given the placement. As soon as I got the plug out i noticed the side of the socket had water spots on it. Like when you dip something in water and lift it out, and there are little spots that didn't run out. Uh Oh... did I just dip my socket into a pool of water, remove the spark plug, and let a the pool of water into my engine!?!?!? The top part of the spark plug, above the threads (the part that would be covered by a pool of water) was covered with a bunch of gooey gunk. The plug was shot from all the misfires. I used my cell phone camera to get a good look down in the hole. The photo showed all the gunk that was left behind. I did the best I could to clean up the gunk, and then installed a brand new plug. All of the other plugs looked fine. I am just learning about the PCV system so I noticed something about it as well. I had to take the driver side PCV tube off in order to get to the plug. I noticed what I though was oil had drained out the lower connector. I thought that was a pretty bad seal for oil to leak. Then it dawned on me. Was that water that had got in and was being recycled back into the intake? I really do not know much about the inner working of a engine. If a "bunch" of water got past the plug, either while driving, or a pool when I took the plug out, where does it go? Would all the water have gone down and joined my oil? What parts of the engine would the water have come into contact with? What potential damage could have been done by the water going into the engine? I am draining my oil right now. I am going to let it drain over night and refill in the morning.
Thanks guys for your help with this!!!

Jacked up gunky plug


Gunk left behind after removing plug


After I cleaned up the gunk left behind


Tons of water got in... and was trying to recycle into the intake... but was too heavy and leaked back out the tube?
 
#13 ·
So...........moral of the story would be......Perhaps a dirty engine is a happy engine? Or at least a not-so-clean engine is not such a bad thing after all.

Glad you seem to have found the cause of the mis-firing, and more importantly why you don't necessarily want to keep and engine too clean.

Good Luck

Jerry:cheers:
 
#14 ·
Now you've got me thinking.:thinkerg: I clean my engine EVERY time I wash my rig, it looks like the day I bought it. I've never had a problem and I'm wondering if the "boot" wasn't on tight on your rig. Good luck!!
 
#15 ·
This is my 5th vehicle. I have cleaned every engine the same way and never had one problem! The coil boot was tight, i must have used to much pressure and/or got to close when washing. Definitely a lesson learned here! Yes, I think a little bit dirty engine is a happy engine. Hopefully no long term damage.

Can anyone tell me where the water would have gone, what damaged might have been caused, etc.?
:boohoo:
 
#20 ·
My bad. Yeah. I did drive it to Toyota and back. When I pulled the oil filter last night it seemed that what poured out was more like dirty water than oil :mecry:
I am going to pour the oil from the drain catch container and see how much drained as well as what it looks like.

EDIT: I just filled the oil bottles with the oil I drained from the engine and got pretty much 6 qts. No Bueno! There might have been a little oil left over in the drain bucket since I'm sure there was no reason to really empty it 100% after last oil recycle trip. So while there is no way to know exactly how much of the overage was water... it is probably safe to say at least some of it was. Oil looked normal for the most part. Nothing stood our as far as water being separated from the oil, etc. A far as color goes... this oil I drained was in for less than 1,000 miles and it is new oil (switched from RP to Amsoil) so not used to Amsoil dirty look anyway. I had randomly ordered new plugs before this all started so I will be changing all the plugs monday or tuesday (even the new cylinder 6 plug I installed yesterday).

FJ Dude, you mention spraying seafoam down in the plug hole. I am familiar with seafoam going into the intake but have never actually used the product. Are you suggesting spraying it with the plug installed or with the plug out and down into the actual combustion chamber? I see seafoam makes many products. Which product specifically (probably only two of their products would be to choose from) would you suggest I use?
 
#19 ·
I would run 5 qts of cheap oil through it, start it, then drain it and put in some good stuff. Nothing you can do about it now but try to get the majority of it out. When you drain it look for any white spots in the oil. My guess is your "A OK" with such a small amount of water and so much oil on all the parts. I would probably spray some seafoam down the spark plug hole then check the plug in a day or two for deposits and clean it
 
#21 ·
Any water from that plug area would have gone into the cylinder on the top thus into the combustion area not below the rings into the oil area. It would have been burned off.
 
#22 · (Edited)
Hmmmmm.... so my extra oil problem is either oil from the previous oil change or there was 6 quarts in the engine. I always let it drain overnight so wouldn't that be long enough for all 5.5 qts (or pretty darn close) to drain out? And I know I put 5.5 in last time. Doesn't make sense that using the same allowed draining time as last time that an extra half quart would have drained out.

Can I expect any other problems related to the water getting into/burning off from within the combustion area?

Other than the seafoam recommendation (which I still am not sure exactly what to do there), is there anything else I can do to "fix" my screw-up or prevent any other damage?

thanks
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top