2013 Tacoma- Code P0301

Hello I'm having trouble with my 2013 tacoma and I'd like some advice on what could be the problem. Its a 2013 with 92k miles, and the 4 cylinder 2.7L engine.

When I was leaving work today the issue happened. When i turned on the truck, for about 10 seconds after it started the truck vibrated pretty strongly. As soon as it stopped the check engine light came on as well as the "trac off" light. It ran completely normal after that. I drove it to auto zone to use their reader and got the P0301 code. Their computer recommended to change the spark plugs. I already intended to change the plugs so i already had them on hand. I plan on changing them tomorrow. Also, the problem hasn't replicated itself when turning it on/off again. I think it has something to do with the engine being warm already. I'll edit this post later if tomorrow morning it happens again after sitting all night.

Is this an issue anyone here has heard of before? What could be the problem with my engine? Googling around I've seen everything from bad spark plug, coil, coil wire, to cracked head gasket.

 

Simplest check would swap plug #1 with plug #3. And coil #1 with coil #4.
See if the misfire follows the plug, the coil or stays at #1.

But changing all the plugs is not a bad idea. Not if they need changed.

If you change all the plugs. Just swap coil 1 with coil 4.

 

I just replaced all 4 spark plugs and swapped coils 1 and 4, and coils 2 and 3. I didn't mean to swap coils 2 and 3 i just did accidentally and didn't feel like taking them off and retorqeing them down to spec. So far the problem seems to have gone away. No vibration at start up. I removed the battery clamps so that reset the check engine light, it hasn't come on again. So far so good.

 

Update : the issue is back. Same code P0301. I swapped coils 1 and 4 when changing the plugs. Idk what could be wrong

 

When you swapped the plugs, was there any oil on them? Especially #1. What color was the electrodes? Were all the plugs similar in color or was #1 plug way different than the rest?

You have a new plug and a different coil on #1 now. So it could be a bad new plug, wiring to the coil or maybe some oil getting in that cylinder. I hope not oil.

Someone schmardter than me may have better ideas and maybe a wiring check if that’s suspect.

Edit: your username sounds very painful and inhumane. Ha!

 

Does it only happen on start up?

 

It happens only on cold start up. Vibration goes away after 5-10 seconds.

 

I didn't notice the electrodes being any weird color on the old plugs. I did notice the little little rubber cup around the center electrode was slightly redish/brown. And the base of the ceramic on the bottom where it connected to the metal body/threading was rusty looking color.

What confuses me is that the problem completely went away for like 2 weeks. So changing the spark plugs was effective, but maybe it only temporarily covered up the problem.

Could there be something wrong with my electrical system supplying bad power to the coils? Maybe a low battery or something?

 

Since it happens only on a cold startup.
I'd want to have a look in the cylinder.
Could be a leaking injector or coolant in the cylinder.

Have you noticed any coolant loos?

 

No i haven't. But my coolant is low.

 

A miss on cold startup can be a sign of a bad head gasket.
coolant can leak into the cylinder over night when the truck is cool.
When you start it back up, there is coolant in the cylinder. The coolant will cause a misfire until it gets pushed into the exhaust.

I'm not saying that is you problem. It may not be.

Have you been loosing coolant?
Or did you just now notice it was low?

 

Could a low battery cause a mifire? Just checked and my battery is at 12 volts exactly when the engine is off.

 

No. Not likely.
Even if it "could", you'd see it on all 4 cylinders.

 

Just checked now and the coolant is about 1 inch above the "low" line on the reservoir. But the strange thing is the missfires dont happen at every cold start. This morning I started the truck at 1pm and it hadn't run since 9pm yesterday night. It started up no problem with no vibration or anything.

 

How is the level inside the radiator?

 

IMO you describe about as good of a plug color as you’re likely to see with today’s gasoline. Ultimately, you want to see a carmel color. But that take a Time Machine to go back to the 70’s each fill up. Or expensive avgas from an airport.

 

I decided to let it completely cool overnight before looking. The radiator is completely full of coolant. When i took the cap off it was maybe 1 inch from below the rim of the opening. It came right up to the overflow tube that leads into the reservoir. Also, after letting it sit overnight, the coolant level is now below the "low" line on the reservoir. I suppose i should fill it up.

 

Update: im not sure what happened. The vibration at cold start just stopped all together and the lights on my dash have gone away by themselves. Its been fine the last 4 days.

 

did it ever occur again?