P0302 Cylinder 2 Misfire

Need some professional advise I have a 2004 Tacoma 3.4 that occasionally will misfire on start up then smooth out and hasn’t thrown a code until today.

This evening I started it up and it was missing and through code P0302 cylinder 2 misfire I replaced the coil pack and plug wires and it’s still throwing the same code.

I’m thinking it’s a fuel injector on cylinder 2 or maybe a bad spark plug. What do you guys think? TIA

 

TG....
I dont know shit about the 3.4L, do they have head gasket issues?
Sounds like sitting overnight, coolant leaks into the cylinder, slowly clears out after you start it...
Pressure test overnight & inspect with a borescope.

if you think an injector is leaking, you can see if fuel pressure bleeds down or if easy enough, swap injectors on a few cylinders & see if the misfire moves.
You mentioned bad sparkplug, can easily swap one out, look for traces of coolant color on the edge of the electrode arm....

misfires that only happen after sitting overnight & clear-out shortly after starting throws the dreaded head gasket vibe in my book....

 

I had a 4.0 sohc in an explorer that had 250+k on it, did the same thing...
Last thing I was think was head gasket as theyre not prone to that...
Plugs were original so changed them, continued...
They are prone to lower intake gaskets flattening & causing vac leaks cold & can misfire...
changed them, continued...

last thing I thought was coolant intrusion, but, thats what it was....

 

Thank you Slater you are always looking out for TW members!

It doesn’t misfire every time it sits it’s only done it twice in like three weeks until it finally through a code this evening. I sure hope it’s not a head gasket and I haven’t heard of issues with these engines and head gaskets.

It’s a little work to get to the fuel rails and injectors so with 252K miles I may just replace them I know it’s not good to throw parts at it but I’m sure it needs injectors.

Is it possible cylinder #2 injector has just been going out or getting clogged since the misfire was intermittent?

 

Excellent Advice

tOp
B4 you load parts cannon
Determine what exactly is the issue

I.E.
If you spend some wrench time swapping injectors like Slater says….and code moves….there u go!

search injectors here

you will run into posts about MotorWest and about $75 eBay injectors (and other vendors)
I used MW after 1)not listening to other well seasoned members here and 2)getting scammed by eBay vendor for crap injectors

 

Yeah, I can’t go wrong with great advice from members like slater and yourself! Thanks

 

Keep everyone posted please!!!

wrenching not always Sunshine and Rainbows…..
But
While your in there
Pull #2 plug and 2 other easy access spark plugs
Hopefully same-ish looking
If #2 is rusty/wet…not good

let’s just cross that bridge when we get there!

 

Is the coolant level slowly going down?

Check it cold every morning before starting the engine. Right at the radiator cap

 

I will definitely do that.

 

I will check this morning. Great idea! Thanks

 

I would do a leak down test on it first..easier than swapping the injectors

 

Yeah, cylinder #2 is easily accessible. Thanks

 

I went out and checked the coolant and it was about three ounces low it’s been a year or longer since I checked it. What’s really strange I started it up and it runs as smooth as glass this morning.

It’s a secondary vehicle so I’m just going to leave it parked and next week do a leak down and compression check on cylinder #2 and if that checks out good go from there.

I will update you guys when I get more into it….

Thank you all for such great suggestions!!

 

If a good injector is that cheap, toss the cannon at it....
but before doing anything PT the cooling system overnight & eliminate the small chance that its coolant intrusion....
The misfire just for a few seconds, smells like bad news...
Eliminate, excessive oil in the cylinder from rings or valve stem seals
scored cylinder walls, etc....
Look in the hole & make sure she's healthy & no red flags....

 

I got a little time pulled no. 2 spark plug no signs of antifreeze so I’m leaning towards the fuel injector.

After I put the one plug in I drove it for about three miles ran perfect. I parked it went in the house for ten minutes came back out missing again.

 

Leave the plug out, pressurize the cooling system and check for coolant mist or dribbles going into the cylinder

 

Will do. Thank you!

 

Update: replaced all the spark plugs this morning and they all appear to be burning exactly the same so I’m thinking more towards the injector on cylinder #2 intermittent misfire instead of blown head gasket.

 

I hope youre right & im wrong!
I like how all the threads are gummy / dark, theres no way you have an issue in every hole, so thats a good sign.

can you lift the injector out & leave it attaches to the rail, just turn key on to pressurize system & see if over time the injector is dripping fuel?

or is that too much work & easier to just replace...

 

I remember using anti-seize on the plugs so that’s probably what is causing the dark threads.

I have to pull upper and lower intake to get down to the injectors so not sure which way I’m going next. I may go ahead and do a leak down and compression check on #2 before I proceed.

I know you have probably forgot more than I know lol so you are probably correct in your assumption. I just keep wishful thinking lol.