Coil packs frequently going bad

At least 1 or 2 every year randomly go bad, usually the same one it seems. I feel like these shouldnt go bad that freaking fast. I had gotten an ECM code recently I'll have to see if i can find the code. I also have the O2 code that no matter what ive tried won't go away. Starting to wonder if my truck is just dying and time to get rid of it. Idk. Anyone had issues like this. 2005 tacoma prerunner 4.0 v6

 

Are you running Denso replacements?

 

You could have a diode wheel going bad on your alternator creating dirty power, have you measured alternator output on a scope and checked ripple?

 

Just use oem parts. Have you kepted up with the maintenance?

 

I had alternator tested at auto parts store not sure what they check exactly but all showed good to them.

 

Sparks plugs, oil/ filter, air filters, coolant etc. Not sure what else to do aside from that stuff

 

Coil packs I've tried denso and other brands same thing happens

 

Faulty alternator, sounds like dirty power. They should last 100k min.

 

What are other symptoms of dirty power to look out for?

 

Pop the #4 coil out and see if it’s dry or wet at the plug. If it’s wet, it’s time for valve cover and spark plug tube gaskets. Good luck!

 

Thought this and had it checked, i did have to replace battery 2 weeks again that was causing some starting issues. The battery was so bad when it would get hot and ground itself out from bad cell inside. Wonder if this was culprit and im just getting issues popping up now

 

I'll definitely check that. Valve covers haven't been done so theres good possibility

 

When did you do plugs and how did they look? For the cost and age of the truck I'd put in a new alternator. Just my .02. I'm not having issues but at over 200k and due for a belt so replacing mine.

Not a fan of telling anyone to throw parts at a problem without testing and proof so you should keep testing. I have an old no name battery charger with alternator tester built in that has proven handy.

 

All plugs looked good, my concern is it seems to always be the same coil pack. The comment about valve covers gaskets i didn't even tbink about, so there that too

 

I've got over 350,000 miles. Original coils.

Coils will go bad if the plug gap is too wide, as it now has to generate a higher current to jump the gap.

If you're not supercharged, plugs in the V6 are supposed to be replaced every 30,000 with copper plugs.

 

Maybe the misfire code at #4 isn't being caused by a coil pack. A good tech can scope the primary (control) side of that coil and see if the pcm is controlling it correctly. And also verify harness integrity

Same for the b2/s1 oxygen sensor

That processor code is kinda bad news

 

If the coil is really going bad then swap it to another cylinder with another coil pack and see if the fault follows misfire to that cylinder as well. Multiple issues at play here with downstream sensor also, numerous reasons could be causing that issue. I would baseline and chase the misfire first. Zero out codes, swap coils to another cylinder and see if code follows coil.

 

I am skeptical that you have coil packs failing. I am old, have had many cars and worked on all of them... and have NEVER had a failed coil or coil pack. IMO there is something else going on. Hope you get it sorted...

 

The P0606 concerns me that the PCM is going bad, if it is then chasing the other codes is moot since bad PCMs can flag false codes.
I would first verify your battery is good and power and ground at the PCM is good as low voltage can also set false codes.

 

Thought that as well...processor code disappeared and hasnt come back either though. Hope i domt need a new ECM/PCM still cheaper than a new car though