ok so plugs are in and coils swapped. It shook yesterday leaving a store and I was hoping for a code as it was getting stronger waiting at a red light, then it just kind of worked itself out. Stupid reliable toyotas! Give me a code!

I'm thinking if it gives me P0302 it's the coil pack (bc that was on cyl 4 before).

If it gives me P0304 then it's the fuel injector bc of the solenoid issue mentioned above.

Is that sound logic?

p0304 came on today. Also unlike before where it resolved, the shaking got stronger at 50 mph. so I'm assuming it truly is the fuel injectors.

Any evidence of rodents hanging out under hood?
Their chewing on wiring can cause lots of electrical issues with the easy access and delicate ignition system.

This generation is pre soy-based insulation on the wires, so this is less likely... but not totally out of the realm of possibilities.

-Charlie

no evidence of that no. I'm awaiting new injectors from MWP. I did pour another bottle of fuel injector cleaner at my fillup yesterday. I stopped three times today during errands and it was ok starting up.

Also...soy wires? wtf this damn soy is everywhere

Agreed unlikely-but I first experienced on a old work 1995 Dodge 3500 Ram van. They camped, pooped and ate wiring. Consumed a few injector wires, insulation and the thin stranded copper.
I was able to solder splice in several inches and then taped it up with Honda Anti-rodent electrical tape. No repeat problems-but placed " bait stations" under vehicle.

I did get the start of a mouse nest in my airbox on the 4Runner when I had it parked for a while with the deckplate airbox port open...

But our later cars ('16 Odyssey, mostly) shows more rodent evidence in the bay than anything else we have. It is too bad the Honda Capsaicin tape is so expensive.

-Charlie

put the new MWP fuel injectors in today. Rounded off two fuel rail bolts while at it, so had to rush to a local toyota to get new ones. It's always something.

I had a new fuel pressure regulator laying around for a while (been having slow warm starts for a few years) so threw that in too.

I did confirm that injector 4 was out of resistance spec, 17.8 ohms vs 13.8 (others were about 14). So I'm assuming it was the solenoid of that one, or something with that specifically. Ironically it didn't run rough until today when I ran out of gas (with the fuel injector cleaner) and after topping off I started it up to head to toyota and...misfire. So it seems like those fuel injector additives really are doing something.

oh and there was blanket material under the lower plenum, so a mouse was chilling there for at least a few days. No poop however.

drove it around today which included several stops and it seems to have been the only issue. I'm curious to see how warm starts go. Typically I have a long crank to turn over. Today I didn't notice that, I'll be pleasantly surprised if this was it all along.