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

$57 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

$57 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