Misfiring cylinders in a 2017 tacoma V6

I have a 2017 V6 4 x 4 Tacoma that recently had some issues with misfiring cylinders. I was driving to work and had some rough idling at a light and then the check engine and trac off lights came on. I was getting codes for 1-3-5 misfires and P030027 (random/multiple) and P160500 (rough idle) I needed to get to work so I dropped it off at a shop to diagnose it and then headed to work. They called me to tell me it was two of the coil packs and then it would be $2000 (!?) to replace them. I decided to get six of them myself and put them in. They told me the two bad ones were on the drivers side which is odd to me because I thought 1-3-5 were on the passenger side. I replaced all six coils, did not see anything else that looked off. Spark plugs were done in May 2022, about 8000 miles ago. I still am getting rough idling but this time it’s just throwing P030027 and P060500 and cylinder 5 misfire, not 1 and 3. Only thing I can think of that’s off is that when I removed the bolt for the cylinder 5 (passenger side, closest to firewall) coil, it was way tighter than any of the other ones and the bolt head actually broke off as I was removing it. All the others came right off. I replaced it with another 6 mm diameter ball but I also noticed that when I was placing the coil pack there was a little bit more resistance than for any of the other five. I pulled it out and looked in there and everything seemed fine. I’m not sure if there’s anything else I can try or if I need to give up and take it somewhere. I’m pretty frustrated after all this money and time I’ve spent doing this. Need to get to work somehow.

 

Did you use a dab of dielectric grease on the tip of each coil pack? Did you also check to be sure all spark plugs were still properly tight? My son's prior vehicle (Honda Fit) had a misfire and it turned out to be two loose plugs. One coil had soot all over it. Dodged a big bullet on those loose plugs...and it was a known issue on that vehicle for some reason.

 

some of them came with grease on them already. The ones that didn’t I put some on. Not a ton though, maybe not enough? I did not check if the plugs were tight but I’ll try that now thanks.

 

This might help.
https://www.youtube.com/watch?v=PPIeyxbnUkg

 

I made sure plugs were tight, it’s now throwing the same codes as the original problem. I’m not sure what it could be at this point. But I was told that my injectors are ok. We will see I guess..

 

Those plugs while newer, may still be fouled. New coils means only that they are new, it does not mean they are good. You could have chewed wires to your injectors or coils. You could have low compression in an or more than one cylinder.
Trouble shooting is a process. Before replacing a coil, it is usually wisest to test it. Ohm it out, or move it to a known functional cyl, and then make sure the problem moves with it.

I would recommend you come up with a trouble shooting plan. The move steadily thru it.

What kind of plugs did you install?
If they were not factory spec denso I highly recommend replacing them with factory spec.

Cheap coils are cheap for a reason. I don't know what you bought, but if they are (NOT) toyota factory, again I recommend replacing them. The cost savings comes from quality and materials. The companies that make knockoffs make more profit than the quality manufacturers.

Since you will be replacing the plugs, I highly recommend a compression test.
Misfires destroy catalytic converters. You can do 3500 worth of damage quick.

I hope this helps.

 

Pull cylinder 5 spark plug out. Any cracks in the porcelain? No fouling? Electrode looks ok? If so move cylinder 5 spark plug to another cylinder and see if the misfire fault goes to that cylinder.

 

Sounds like a possible fuel pump and or fuel rail pressure regulator.

 

Adding to the comment about getting coils from the dealer . . . I had a '99 tacoma and the 3 coils (yes, it had 3, not 6 on the 3.4L V6) never lasted more than 3-4 years. i was not buying them from the dealer.