Spark plug replacement then weirdness.

Seeking words of wisdom from the collective.

Replaced all eight spark plugs and now I have starting issues.
Prior to this routine maintenance it ran perfect.

2015 3UR non flex
190,000 miles on the engine

What I used: Toyota dealer supplied Denso OEM plugs. Checked the gaps for compliance.
What I did:
* disconnected the battery
* removed the air box lid and snorkel for access to bank #2.
* one-by-one removed each coil, then plug, then installed new plug, then installed coil.
* reinstalled snorkel and air box lid.
* reconnected the battery.

Started it up and it immediately ran rough and idled low.

Turned it off. Waited a few seconds and repeated. Started up and ran rough.

Turned if off again.

Disconnected the battery for 20 minutes. Reinstalled and it cranked, winding out but never catching.

Upon inspection of the fuse box I found the 10A INJ fuse was blown (see photo below identifying the fuse). Replaced it and repeated. It did it twice more.

Enough of this shiznit. Plugged up the Xtool D8S bi-directional scanner and it's giving these four codes:
* P0352 primary/secondary circuit of ignition oil B permanent.
* P0353 primary/secondary circuit of ignition oil C permanent.
* P0355 primary/secondary circuit of ignition oil E permanent.
* P0358 primary/secondary circuit of ignition oil H permanent.

At 190,000 miles I'm not sure if I should be of the belief that all the coils need routine replacement and the spark plug replacement just tipped the whole system far enough to throw codes.

Below is confirmation of the fuse it keeps blowing. And then a shot of the plugs I removed.

Thanks in advance.

 

I would go back and double check every plug to ensure:
1. It’s firmly seated and clipped
2. You didn’t bend any of the male side pins when plugging back in

 

The scanner DTC reports the coils as letters. "B." "D." Etc. Who knows how the coil letters match up with the cylinder #'s? Does coil "A" go, for sure, with cylinder "1?" I can't find anything to confirm the relationship between the two.

 

It makes me think that one or more of the coil electrical connectors got damaged somehow or one or more of the coils has a very low resistance causing that cylinder to not fire and ultimately blowing a fuse.

 

I have no advice but am interested in the outcome. Getting ready to change mine at 188,xxx.

 

Same. A damaged pin could be bent and arcing in the connector. That would certainly blow a fuse.

 

The letters correspond to numbers A=1, B=2, etc. You have codes on both banks, cylinders 2,3,5, and 8. I see two possibilities.

1) Your coils were on their way out and pulling them to do the plugs did them in.
2) The ignition coil wiring was damaged during the job

 

Did you unplug each coil pack wire harness or no? I just did mine on my 2015 non-Flex Fuel and only unplugged #3 on the drivers side because it was wrapped around the main harness and there wasn't enough slack to remove the coil pack to get to the plugs. If you did indeed unplug each harness I would double check the connection. They "Seat" and seem ok but there is a resounding "click" when they are down all the way.

 

Unplug the coil packs for the affected cylinders, inspect the connections, replace the fuse again and see if it blows or not. If it does not, plug the coil packs back in, one at a time until it blows.

I am assuming that the fuse is blowing in “Key on, engine off” state.

Idling very low, stalling, and being grumpy to start are all par for the course after disconnecting the battery on these, until the ECM relearns the idle.

 

My son got a bad coil pack once.

 

UPDATE 1

I did unplug most of the electrical connectors.

I went back around and rechecked all the connections to the coil sticks.

All were good until I dug back deep for cylinder #8. This is passenger side nearest the firewall. Coil #H. And one of the DTC's that is thrown. I had the connection on backwards. Yes. Backwards. How in the hell? Well. This cylinder #8, coil #H, has a rubber boot over it. With how it is all assembled it is very stubborn on you sliding the rubber cover back. Then the natural orientation of the female connector is f'n backwards. And it slides right on backwards (weird). And I'm guessing in the heat of the day I spaced on listening carefully for "the click."

Now.........getting it on in the correct orientation is proving to be stubborn. I think that the prongs have been pushed aside a bit. The access is an absolute bitch and the temp here in central Bamaland is 102*. So I'll try again in the morning when it is cooler.

Thanks to all for the insights.

Here's what the lil' rubber hood looks like: