Intermittent misfire cylinder 4 2009 Tacoma 2.7 liter

For about a year now I have had a minor stumble in my motor. Most noticeable upon start up and randomly while idling. However now I have had two misfire events that put my truck in safe mode.I believe the code was p304 Misfire on cylinder 4. I changed the coils after the first event and drove it for two days before it happened again. Both times it has happened upon start up when I was in a rush. Most of the time I let my truck idle down and run smooth before I go, but these times I just went. My next step is fuel injectors, but I feel like I have a sticky valve. I have done a compression test but not a leak down, compression was all 140 and above. What do y’all think?! Also the code reset itself as I pulled it off the tow truck the second time, therefore I didn’t get a code the second time.

 

Time for valve cover and spark plug tube gaskets. Good luck. Edit: pop the #4 coil out and see if it’s covered in oil

 

There was no oil on the old coils. All the spark plugs looked the same too. I just replaced those about a month ago.

 

easiest thing. If its consistently on the same cylinder, swap one thing at a time. First, swap the coil pack to a different cylinder, see if miss fire follows. If yes, new coil pack, if no, swap coil pack back, see if it occurs again. Once it occurs again, swap an injector between two cylinders and see if it follows.

 

I agree.
Swap the coil and plug.
Swap #4 coil to #2
And #4 plug to #1
I don’t like to swap parts to the cylinder directly next to the problematic cylinder.
Some time, you’ll get false reading on the adjacent cylinder.
See if the misfire follows.

If you have a scan tool you might look at freeze frame data and any pending codes.

 

The misfire dosnt happen all of the time so it can be hard to reproduce. Also I swapped the coils already, even though they were new. I’m reluctant to play around with fuel injectors. I figure I might as well get new ones if I’m taking it apart. I stethoscope the injectors too and they sound the same.

 

Regarding spark plugs, did you stick with Denso or NGK iridiums?

 

I’m pretty sure they are ngk. But I would have to pull them out to check for sure