05 Tacoma - P0306 - Need your help

Alright, this weekend was a frustrating one for me, ending in a P0306 (Cylindar 6 misfire) - ugg.

I need your input to help me figure out what to do next. I've been trying to research the issue on this site and have seen a multitude of solutions. I'd like to get some advice so I can narrow it down to just a few things to try. If all else fails, I guess I'll go to the dealership .

Here's the specs:

• 2005 Toyota Tacoma Double Cab SR5 - v6
• 140,000 miles
• K&N Air Filter
• Spark plugs replaced in last 25K
• I'm not a mechanic, and am moderately skilled at best in vehicle repair (but always willing to give things a chance)

Here's the details:
About two weeks ago, I followed two great posts on here about cleaning out your Taco's throttle body and cleaning the MAF sensor. I followed those to the T. Past the initial firing up, the truck had a much better idle, was a bit quieter, and was getting better fuel economy .

Another issue I was having was that when I would come to a stop on cold days, my heater would stop putting out hot air. So, this last weekend, I decided to flush my radiator (using a tutorial). I drained all fluids, flushed, and put back in new Toyota super long life pink stuff. Heat worked like a charm.

While I was at it, I changed the oil in my truck too (I doubt that is a factor, but wanted to throw it out there).

Truck was running fine and dandy.

Next day, I go to start it. It starts fine, but has a strong shake (not good, not good). The shake is there for about 20 seconds, then completely goes away. No check engine, just like it 'had a moment'. I drive to grocery store. Go to fire it up in the parking lot. Again, strong shake, goes away, no engine light. Later that evening, I go to start, get the strong shake, but this time I get the check engine.

I have a Scanguage II, so it shoes me a P0306.

So, here I am with a P0306, a strong shake that goes away after about 20 to 30 seconds, and a frustrated look on my face whenever I'm by my truck.

Could something have worked its way down into cylindar 6 when I cleaned the throttle body? Is this something more serious? What should I try?


Things to note:
-There has been a peanut-butter type substance underneath the oil cap ever since I bought it. I usually just clean it out and chalk it up to moisture - maybe a bad idea? I hope it's not more serious.
-Most of my trucks miles are highway. Only recently did I move close to town and now have mainly city miles.
-My trucks power seems to be sagging (hence why I did the MAF cleaning/throttle body cleaning). This could also be more noticeable as I recently moved into a hilly town.
-The spark plugs were the iridium tipped jobbies (yeah, I probably got taken, and should have read up more on them) and really should be ok.

Alright friends, thanks for any help you can provide!

 

Pull the spark plug on 6 and look at it, make sure you didn't leave a loose connection when you removed the stuff to do the MAF and TB cleaning. My best guess which is a wild one but..... maybe your coil connection was loose and "shaked" loose which makes sense if after time the light finally came on, but I know that in order to get most engine lights to show up the fault must happen a certain number of times. But I would try those before I would go as far as taking it to the stealership, don't get me wrong they do good reliable work and back it up, but they will take your first born child and then some as payment!

 

U gap them?...................do not listen to the "they are pregapped" BS

I never run anything but factory denso/ngk


Would it be possible to swap the coil pack from 6 to another cylinder and see if the problem transfers to the other cylinder?

I just woke up so I may be shooting blanks.......here's to hoping someone else comes in

 

On misfires, start with the basics.

This^^. Swap the coil AND plug to another cylinder. See if the misfire moves. Great place to start.

 

Thanks for the responses. In regards to the coil pack swap... I'm assuming this literally just means to unplug the spark plug wire from say cylinder 4 and switch it with cylinder 6 to see what happens? I hope this is just a spark plug replacement, that would make my day. This still leaves me wonder why the issue goes away after a few seconds though. Thoughts?

 

Sounds like head gasket.

 

Engine heats up, metal expends and seals head gasket.

 

This is exactly what I was afraid to hear. Aside from checking the spark plugs (mentioned above) to narrow it down, is there anyway to test/check that it is in fact the head gasket?

I've heard the 05's had a particular issue with the head gasket. Is this as much of a nightmare as I'm thinking it could be?

 

I believe i got this code on my truck and change out the spark plug it was all good. It was Cylinder 5.

 

Ok, silly question. Should you replace just one spark plug, or is this a deal where you might as well replace all 6 while you're at it?

 

You can do a leak down test on all cylinders then compare them with 6. There is a turkey baster looking thing that using a testing chemical in the coolant to see if the gasket is leaking on that side.

 

Just do all 6

 

i just replaced one which is where the problem was. For some reason my Coil was not seat all the way down. So my Truck started Lurching.

 

Going through the exact same thing myself. Replaced all plugs and issue was still there. Swapped coil pack from 6 to 1 and still there. Have run two tanks of premium with fuel injector cleaner and now only occasionally get a hesitation.

To your issue:

1. Check your radiator for oil and your oil for coolant. Could be a head gasket and if ti is, no sense doing the following steps.

2. Swap your plug from cylinder 6 to cylinder 1 and your coil pack from cylinder 6 to cylinder 2. See where your problem is

3. If the problem moves to cylinder 1, time to change out your plugs (25k is close enough)

4. If the problem goes to cylinder 2, get a new coil pack and put it on cylinder 2.

5. If the problem is still on 6, try a tank of premium gas and some techron and see if it improves.

6. If it does not improve after a tank of gas with FI cleaner, you might have a bad injector.

 

Leak test... Alright, now you've got me thinking about something. One thing that I noted when I replaced my truck's coolant was that the driver's side petcock drained a lot of coolant, while the passenger side barely had a trickle. Is that an indication of anything? What would be leaking in this 'leak test'?

I'm not extremely familiar with how the coolant system works. Would coolant possibly leak into the cylinder?

 

Awesome response. I'll give this a shot... Many thanks for your response! I'll keep you posted on my results (it may be a few days before I get the chance).

 

yea would be interested on what the verdict is

 

This would be a good idea as well. Sometimes a head gasket leak will not give visible sign. The link below is what is being referred to:

http://www.autozone.com/autozone/accessories/OEM-Block-Tester/_/N-25dh?itemIdentifier=391378_0_0_

 

Sorry I missed a word in there. It's a leak down test. It is two gauges hooked up to an air supply. Then another hose that threads into the spark plug bung. You will the cylinder with air and see if it holds it. This can determine if your misfire is due to a leaking head gasket, bad valves, or bad piston rings. A compression test can do somewhat of the same thing. I would swap the coils around first to see if that does anything. It's quicker and you don't need special tools for that.

 

Basics first... Spark and fuel.