05 Tacoma - P0306 - Need your help

Awesome, thanks for sharing.

 

Ok, appreciate the insight! Thanks for sharing.

 

Mostly likely headgasket due to vehicle misfire during cold start, also when you do the leak down test do it cold and look for bubbles in the radiator.

 

Bubbles in the radiator? How do you check for that? Now, one thing to note, is that the reason I flushed the radiator to begin with was the whole not getting heat on real cold days when idling. You could hear the air move through the system when you accelerated. Does that indicate anything?

 

Usually bad headgasket.

 

Alright... I'm bracing myself for that being the issue. I've seen on other forum posts that this was the issue. I have two more questions on that then:

1. How much does replacing the head gasket usually run?
2. Is this something a moderately skilled person could handle, or do I need to consider running to the stealership?

 

You look for the bubbles when you do the leak down test

 

If you do leak test and it turns out to be headgasket you cough that early so all you have to do is change headgasket.
1. Most will try to charge you arm and leg for this, plus they will want to replace half of the endgine and bunch of parts. so you can get quotes ranging from couple hundred dollars to couple thousands.

2. It can be done. If you short on money and want to give a shot. Set aside plenty of time to do work correctly.
Make sure you use torque wrench and have all parts ready ahead of time. Clean engine as good as possible (power wash, degreasers, and blow with leaf blower to make sure nothing gets in the engine while working
Key here is Patience.

 

Yowza... Thanks for the input.

 

Alright folks, I decided to take a breather on this and relax just a bit before going all out on a head gasket issue. Justus/Spoonman/others who mentioned it, I took your advice (with a slight variation).

I swapped out the coils on cylinder 4 & 6 (but not the spark plugs), and reset the P0306. I did just the coils as I figured if I got the P0306, it'd narrow it down to plugs, and if a got a new code for cylinder 4, we'd know it's a coil.

At first it was back to acting like 'all is fine'. But given a few cycles (on/off), it went back to the heavy shake. Again, it threw a P0306 (cylinder 6 misfire). So, I think at this point I'm down to replacing the spark plug(s) at this time.

Still not done with the process of elimination, and not resolved. Just wanted to update you guys/give the trouble shooting path for anyone who googles this in the future.

I'll keep you all posted.

Thanks again!

 

Under normal circumstances, One thing I recommend is to reset the computer when you do things like TB cleaning, changing plugs, etc. etc.. Also, a lot of times a "rough idle" may clean up simply by resetting the computer.

In your case, and with the miles on the truck, you seem to have your problem narrowed down and you have been given good advice. Let us know how it all works out...

 

Before reading on, I already have a good indication on what is likely going on as I had a similar issue, but with my 2.7 on my Tacoma. This is likely what has happened:

Either a head gasket or a bad spot in the cylinder wall for #6. Your description is actually dead on perfect. What you are looking at is: As the engine sits, coolant pressure from the cooling system allows coolant to seep slowly into the #6 cylinder. When you restart your truck, this coolant prevents #6 from properly firing. (also excessive amounts of coolant can cause a hydrolock, so be aware of this) After the engine has run for a good 10-20 seconds, this coolant has been ejected out the exhaust, and the engine then catches proper fire, and runs normally. Thermal expansion on either the head gasket or cylinder wall then seals the imperfection and the engine runs fine. There is a really simple and fast test you can perform to check this. After parking the truck you allow for the proper amount of time for this failure to reoccur (Overnight perhaps) Then remove the #6 spark plug and crank the engine over. If you get a heavy mist, or coolant ejected out the spark plug hole, then you have verified that it is an internal failure. Simple test that takes minimal time.

Very useful tool. Just be sure to follow the directions EXACTLY to prevent incorrect diagnosis.

Head gasket replacement costs will vary from state to state. Assuming an average of $90 per hour, the labor charges will be around 14 hours, so expect $1300 in labor, plus parts cost can be around $300.

Try my suggested test above. Simple and easy. Let us know what you find.

 

Maybe a silly question, but what's the process for resetting the computer (I'm assuming this is different from resetting the P0306 code)? Simple as a battery disconnect?

 

Hey BamaToy1997,
Great insight on that issue, I appreciate the input. I'm going to try out the spark plug test first to narrow/eliminate that aspect. Once I have that down, I'll give your test a whirl.

Ya'll are awesome, and yes, I promise it will be my sworn duty as OP to keep the updates coming.

 

Ok... So here's where we're at.

1. As I mentioned before, I'm still leaning towards spark plugs as the issue. I haven't yet swapped any of them out, but am thinking of doing that this weekend.
2. **Sigh**, all this talk of head gaskets shook me up. So, I decided to pay a local mechanic to give my engine a pressure test (not sure if that's the official name), and to do the coolant test that you guys mentioned. Yeah, yeah, it goes against my very being, but after researching it, the pressure test was more than I was comfortable with, and the coolant test seemed to have a fairly high rate of user error in the analysis. Plus, my guy was very reasonable (~$50). Good news! The results came back negative (hehe). No leaks, no exhaust in the coolant, yada yada. He further confirmed the P0306 and agreed that the spark plugs are the next thing to try.

I still think its odd that my spark plugs, which aren't really that old at all, are an issue. I also find it odd that this is happening now after I did all this maintenance... Just odd.

Anyhow, I'll keep you all posted on how things shake out (pun intended).

 

Alright, back again for an update. So, I swapped out the spark plugs for all new, gapped, Denso's. Put everything back together, and sadly, the shake is still there for just a moment, but it seems to be a bit lighter.

So, we've ruled out header based on the tests I had done, and we've ruled out coils/spark plugs. What to try now? Any chance when I cleaned the throttle body that something is clogging the air from getting into cylinder six?

 

Continued at: http://www.tacomaworld.com/forum/2n...econds-clears-up-help-needed.html#post6840415