Bad coil pack...questions from a Old Timer here.

Long time member, usually don't ask questions but here goes. Today my Taco started shaking like a Conestoga wagon going down Hwy 80 to Longview. Cut the trip short and came back home. Put the scanner on it and came up with the P0300 and the P0305. Random misfire, misfire cyl 5. Been 6 years since a tune up, so went and replaced Wires, plugs and boots. When pulling the plugs the looked like it is running lean (White on the bottom of the dual electrodes) so question 1.....Will Ethanol do that to plugs? Mixture is computer controlled, so no adjustment is possible. Second question....If a coil went bad, would not "Both" cyl 5 AND cyl 2 misfire? Seeing that they come off the same coil pack, never heard of only 1 side of a coil pack going bad, is it even possible?

 

One bad coil pack can make one cylinder misfire. I have had that happen. I'd just swap them around if you can and see if the problem follows the bad coil pack. I've had good luck with NAPA replacement coil packs if you don't get OEM

 

You might have gotten some bad gas.

 

Is it running well since the tuneup ?

 

Start up and idle is fine, not driven it yet. Cleared codes, not returned on startup. A case of the missing 5/8 spark plug socket somewhere underneath. Always something.

 

When I was getting random misfire codes, I was told to put dialectric grease in the spark plug boots. Did and haven't had problems since then. They were new plugs, new wires and check the coil packs as well.

 

Found the 5/8. cleaned the engine, changed the oil and took it to Gilmer (16 miles 1 way) and it came right back. Must be the coil pack. Now to ponder replacing 1 or all 3 at once. Gotta go with OEM.

 

Long time ago I had misfire coming and going and under load.

No codes tripped.

Took me forever to figure it out and it was the coil packs.

They would work most the time and them sometimes act up and the truck would misfire terrible.

The bad coil caused my plugs to crack and get carbon tracks too.

I replaced all coils, plugs, plug wires and never had the problem again.

I did have a similar type problem later with no codes with lack of power
and ended up being bad knock sensors.

Again no codes on either of these problems

 

I just saw a you tube video on ignition coils last night discussing wasted spark ignition systems. What he had to say is that when there is an issue with the secondary system (plugs, plug wires, boots etc) that the spark HAS to go somewhere and it usually burrows a hole in the coil causing 1/2 of the coil to stop working. Is that the case here... dunno, just a piece of info.

 

Mine did that. Completely fried the coil boot.

 

Coil packs are a funny thing.

I had one go out while driving and it literally sounded like I blew the side out of my muffler. Toyota replaced all 4, good to go.

Fast forward 18 months.
I took my Toyota in for an oil change and a new battery.
They called and said to come pick it up.
Drives home fine, no noises.
Parked it for a day and when I get in it to start it, it turns over, runs for 2 secds and shuts off.

Call Toyota, they send a flatbed.
Keep it for a day and call me to come get it.
Free of charge. Said it's fixed.

Sits for a couple days, go to start it same exact thing. Starts, runs for 2 secds, shuts off.

Call them again, they come get it.
2 days later they trace it to a bad coil. No noises, no misfired, nothing.

Call me back, charge me for the new coil pack and it's been fine ever since.

https://youtu.be/nm5QNU49n_c

 

Ordered all 3. If one goes with 242K, the other can't be far behind.

 

I have 2 napa replacement coil packs and 1 OEM one left. I think I should just replace that old one just for peace of mind! It does run fine though. A little stumble it's always had but she still pulls pretty good for a tired old V6

 

Order the Denso 673-1201 from Napa they are real OEM. See the red labeled OEM sticker peaking out.
If I remember they were half as much as dealer.

When I had violent intermittent shaking it ended up being and injector.
There is a procedure to ohm them.
Let me know if you want me to post that.
Five O motorsports was the place to get injectors.

 

I ordered 3 coil packs from Toyotapartsdeal.com. As far as injectors go, I have had 6 waiting in a box for a few years I got off of a OEM parts place going out of business. Even took them to the Dealer to compare them with what they had to make sure I didn't get ripped. Matched perfectly. So I'm good there, and we all know someday they will go.

 

Update:
Replaced all 3 coil packs, Still doing it. My thoughts are.......Could be a Injector, tho it is intermittent and I think unlikely, or it could be the wire from the ECU which I think is most likely on a near 20 year old truck in Texas heat. I can't screw around with this just guessing and throwin more parts at it, so I took it to my shop. If it is the wire, let them mess with it.

 

Catcrazed is the winner!!!!
Took it to the shop, and they found that even tho the injector was working and showing the correct resistance and ohms, when it got to a certain temp, it failed. I had a box of 6 injectors I got from a place closing up a few years ago for cheap and had them replace all 6 while they were in there.

 

Glad you got it figured out.

 

Hope that's my problem. CEL and Code 3001. Swapped the coil pack with the one next to it. CEL and Code 0301. I removed the fuel rails and am waiting for my rebuilt injectors...