P0304 code

So i have a p0304 code does this mean the number 4 cylinder or is it just a generic code? I change all the plugs with new ones and swapped the ignition coil number 4 for the number 2 cleared the code and 80 miles later it returned i scoped the cylinder looks black not shiny like coolant is inside the best I can tell so maybe the fuel injector is bad can I test it with a scanner?

 

its not a generic code, cylinder #4 misfire....

 

First you need to determine when the misfire is occurring, cold start, idle, under load, all the time, etc

 

It will trigger the code on start up with in first minute in the morning I know some say coolant but can it be a leaking fuel injector? The truck runs fine after about a minute I just have a basic obd scanner that shows possible causes so I was looking to buy a bi-directional or something new they will so misfire and test injectors

 

That suggests a headgasket seeping coolant in a cylinder, relatively common on early 4.0L engines
I'd be looking in the no 4 cylinder with a borescope with the cooling system under pressure.

A seeping injector will typically cause a long crank when hot because the intake manifold will fill with fuel vapor and flood the engine at startup.

 

could very well be an injector....
top_dog has an 04 & he was chasing a misfire....
From his description I was screaming sounds like a head gasket...
Misfire cold for a few seconds....

He tossed a fuel injector at it & fixed it.
No idea if you guys have the same engine, his profile is on lock-down, couldnt find the post.

 

I used a borescope the top of piston was black carbon not silver like new I will try to get the photos of the sd card but maybe wet so maybe a small leak in hg

 

if its just a tiny bit of coolant, the piston top can still be carboned up.
true way of knowing is pressure test the cooling system overnight & send the borescope down after it stays under pressure & have a look around the head gasket seam at the top of the combustion chamber, not just the piston top

 

Ok thanks this is the info I get from my scanner also say could be pcv, mechanical or ignition that’s why I was looking at fuel injector

 

Reread post #5 above, that is what you need to do next.
That's the next logical thing to do. You'll see where/what/if fluid is leaking.
Throwing an injector at it is bad practice. Amazon sells borescopes pretty cheap.

 

OP, here is the link to my thread slater is talking about you can read through it and see if anything helps diagnose your problem.

https://www.tacomaworld.com/threads/p0302-cylinder-2-misfire.860449/page-2

Note: My misfire only poked its head up when hot it ran fine when cold.

I could start it up cold get the engine warm then shut it off for 15 minutes restart and then the misfire.

 

OP, I was just reading that the gen2 Tacoma came with Denso fuel injectors factory installed.

My gen1 had the Aisin factory installed injectors so my thread may not be of interest to you.

 

Thanks I have a borescope cheap one from Amazon but guess will have to get a pressure tester to see I can see coolant in the cylinder was hoping for maybe 6 injectors and couple gaskets not head gasket and more things that come along with it $$$ but I do have a appointment with dealer on Saturday see what they say if bad might have to let her go

 

think you meant #8....
could be wrong, sounds like he has a horoscope, if not, needs one...
& a cooling system pressure tester, think some parts stores loan them out....

 

No, I meant #5.

Specifically this part.

And yes, a coolant system pressure test kit will be needed.
Unless OP want to wait over night and hope enough coolant is in the cylinder to puddle. Which isn't always the case. Pressure helps see it bead up and run down the cylinder wall.

 

I had it backwards, I dont remember this morning....

 

So after about 10 key cycles the code went out but still going to check with borescope when I get a pressure tester

 

This is what you will typically see with a headgasket leak, this one was pretty bad but gives an idea. Sometimes it takes quite awhile for a drop to form.