Ignition coil woes....

2009 2.7L M/T 4wd regular cab

So I posted about changing my valve cover gasket last January and since I was coming up on 300,000 miles I asked if there was any preventative maintenance I should do. Someone suggested changing the ignition coils so I did. Changed all four to NGK coils I bought on Rockauto (this was a mistake). In about 15,000 miles around June I started having some rough running symptoms/low power and I drove it that way for another month. Finally I got the flashing check engine light and limp mode. Took it to a mechanic, identified a bad coil. Replaced it. Literally 5 miles later I had another one go bad. This time I bought a scanner and diagnosed it myself. bad coil.... Long story short I've been through 5 coils of various brands in the last 4 months. I just replaced one and I still am getting a small miss but not enough to trigger limp mode. Would like to know if there is something I'm missing either when installing new coils like retuning or is it something else frying them like excessive idling? (I was living in my truck for a bit while traveling), ecm?, attachments? . The only additional thing I have is a 1000watt inverter wired in but I keep it's breaker off.

side note I just rolled over 300,000 miles yesterday and would like to put 300,000 more on it.

 

These are OEM coils?

 

It’s probably the aftermarket coils.
But the wrong spark plugs, worn plugs, and bad insulator boots can contribute to coil failure.

Has failure occurred on different brand coils, and different cylinders?
When was the last time the plugs were replaced or pulled for inspection?
As well as the boots inspected?

 

I would start by looking at condition of the plugs. I have run Denso coils from Rockauto on my truck and they are a good option. The OEM manufacturer is Denso, I believe.

For the plugs the stock ones are

$53 Denso SK20HR11 ---- IRIDIUM PLATINUM power pack Spark Plugs -- # 3421 ----- 6 PCS NEW

Denso SK20HR11. They are the iridium flavor so they should be good for 100k miles. Interested in hearing what you find, good luck!

 

Did the VC gasket get done? Are the coil boots coming out wet with oil? What kind of plugs are in it?

 

Installed new iridium plugs when I redid the valve cover gasket ~15,000 miles. I used the plugs listed in the manual. Don't have it next to me right now off hand. Coils are dry, no oil. Failure cylinder appears to be random and with multiple brands. DENSO 673-1308 are the coils I see listed on Rockauto. I haven't had time to contact a dealership to see what was oem ( I work some crazy hours during the week right now). What are the "boots" for a coil on plug setup. I'm used to vintage vehicles where there is an actual boot and wires.

 

The boot is the rubber piece on the bottom of the coil that snaps over the plug.
Denso doesn’t sell the boot separately.

About the only time I replace them (if applicable) is when the old ones are oil soaked or when the plugs show signs of carbon tracking.

Boot


Carbon Tracking

 

Spark plugs... Really check the. Spark plugs you may have crack the porcelain.

 

They're available.. I used a set on 2.7 today that got a valve cover gasket

https://www.partsgeek.com/2mmptpj-toyota-tacoma-direct-ignition-coil-boot-kit.html

 

Yeah, I just did a brief search for Denso boots on the 2009 2.7.
Didn’t see any. But I just looked on the Denso site.

I know they are available for the 4.0.
And I also know you can get the spring turned the wrong way too.
We just went over that not long ago. It happens.

 

Did you replace the spark plug tube gaskets when you replaced the valve cover gasket?

 

Sorry for the long delay. I am a warm weather warrior and have been absolutely swamped with my new job. I did replace the spark plug tube gasket when I replaced the VC gasket. Pulling the spark plugs right now. I installed

$53 Denso SK20HR11 ---- IRIDIUM PLATINUM power pack Spark Plugs -- # 3421 ----- 6 PCS NEW

Denso SK20HR11's when I did my VC change and I have brand new ones ready to go so I will swap them.

 

photos attached for the plugs. No apparent carbon tracking. Coffee color on the ends. Gaps are all at 0.039. Installed new plugs gaps all at 0.041-0.043. Have an 8 hour road trip tomorrow so I will have a good opportunity to see how it runs during that time.

 

Did you throw out the oem coils? If they were working well I would have kept them as backup. Yec Flamma makes good aftermarket coils. They are a Japanese manufacturer. I have three in our Lexus ES; the oldest is five years old and holding up well.

 

Sadly yes, I got rid of all but one. Hindsight is 20/20 I wouldn't do it again.

Edit: Got through my road trip okay. Feels like I have a little more power on the hills, that said I have a pretty bad shimmy that I need to address before I can feel for misses

 

Hoping this is not a dead thread.
I have a '09 V6 Taco and I seem to keep dropping coils.
1. Developed a miss, replaced a coil (#4 maybe). Still had a miss but ONLY under load so I could not find it.
2. Shop found it with a laptop while driving under load after it warmed up. It was #4 and mechanic said I must have bought a dud coil from Advance.
3. Drove for about a year and got another miss. Coil blew up, not sure which one but it was melted. I said F it and bought 6 coils from the dealership, put them in and drove for a couple months. 4. pulling away from a corner it started missing so bad I could barely move the rig. Got home and figured I should have just done plugs too. Ordered 6 plugs from dealership, installed, still missing. All plugs black as night but evenly black, no cracked ceramics or physical concerns. I pulled the codes and #4 and #6 are missing. I popped off the wires and miss was unchanged so basically confirming those coils are not firing. Tomorrow I will swap the coils around and see if the miss moves. (no, I did not keep the previous coils)

BUT.... don't you find it WEIRD that I keep dropping coils??? I have never seen anything like this.

 

I can't comment on the dropping coils as far as why or what's going on, but considering you're seeing that with OEM coils, YES, that's definitely a very weird issue and likely means something else is going on that needs to be fixed.
Autozone specials, sure... but OEM or Denso (technically OEM).. no.. those should last a good long time. I've got the original coils in my 2010 Corolla and they're still going strong.

 

Hey guys, I've been meaning to post this for a while in the hopes it might help someone else in the future.

A few months back I noticed an ever so slight "stumble" in how my 2008 Ext cab 4wd 2.7l 5spd with 278k miles would idle.

It wasn't awful and only at idle and there was no CEL thrown.

I was also noticing the weirdest behavior where when I'd drop down to 2nd gear - typically when making a turn while driving "in town" it would bog down and either have to give it a lot of gas or drop into 1st (both awkward options).

Given the behaviors and my knowledge and experience (I'd call myself an "experienced amateur"), I was thinking likely my fuel pump was starting to poop the bed and it was time to explore doing some pressure tests and getting up to speed on reading the ODB2 data (my previous 4x4 was an ODB1 Jeep XJ)...

Then seemingly out of the blue I get a CEL on startup. I pulled out my code reader and it showed P0303 - misfire on cylinder 3.

I cleared the code and begin researching.

Shortly thereafter, I'm getting on the highway to go to work and have to hammer the gas due to an oncoming 18 wheeler and the truck was not at all happy about that. Flashing CEL, bogging down and forcing me to pull over. I give it a minute, seems ok, no stored code oddly, but I put the scanner on it anyway and again, P0303, pending.... the engine was running smoothly, so I continue to work without further incident.
On the way home, the truck is again, not happy. I have to pull over a couple of times, flashing CEL, etc.

Obviously at this point, I can't drive the truck until I fix it and figure given the consistency of code and what I'd read on the forum while researching, that my prime suspect was a bad coil.

Sure enough, my #3 coil was bad and replacing it corrected all of the bad behavior I've described above.

Now I have the joy of adding "tune up and replace the other 3 coils" to my to-do list for this truck!! The old coils were some unmarked aftermarket brand the previous owner used and given the cost of a new OEM/Denso coil, I bought 1 from the dealership at 2x the Rockauto price to get me back on the road.