Likelihood of 2 injectors going bad a year apart? (3.4L Repeat misfire issue when truck is warm/hot)

Hey TW,

Just wanted to get some insight on this super annoying issue that has come back again after a year. This is the backstory:

-Last year I went away on a summer trip for a week with my family, truck sat at home for a week. Came back and was having misfire issues. Truck ran perfectly fine from a cold start, but when I'd start my truck when it was warm, like after going into the store and coming back out, it would misfire right after starting it up and continue while driving.

-Scan tool gave a P0306 code, misfire on cylinder #6. Read countless threads on different yota forums on the issue and 90% of other people with the same weirdly specific issue ended up having an injector issue. Wanted to get the easy stuff out of the way first so I cleaned my MAF sensor/throttle body/IAC, installed a new fuel filter and dual electrode plugs + wires, swapped coil packs. No dice

-Gave up and took my car to a trusted shop. Mechanic said it was indeed a bad injector #6, replaced it and truck ran like butter with no issues.

-Fast forward almost EXACTLY a year later to this month, and I went on the same summer trip again with my family for a week. I come back and my truck is doing the same exact thing, except this time around it'll clear up after anywhere from 10 seconds to 5 minutes after starting it and driving it around. Check engine came on today and scan tool is reading P0305, misfire on cylinder #5 this time......


Does anyone have any suggestions on how to proceed with this headache, and possibly have an idea of what the cause might be? I feel like the circumstance of my truck sitting for a week in both instances has to be some kind of factor in this, unless I'm just unlucky as hell. Plugs, wires, fuel filter all have less than 15k miles on them right now

I'm honestly planning on just saying fuck it at this point and spending a day to replace injectors #1-5 myself so I don't have to deal with this crap again in the future.

 

Given the age of your truck, I'd say you're gonna lose more of them, as mechanical items wear out with use and age.

 

Either have these refurbished or buy a used set to have refurbished and swap them when they come back.

If buying new just be careful lots of knock offs around.

 

If I were doing it, I'd buy five injectors from Motorsport in Canoga Park, CA. They refurbish injectors and ship them for a decent price (ca $200 for six).

 

If one injector went bad it's not unreasonable to assume the others are going to fail soon too. Heck they're all 18 years old.

I always give the customer a price to replace all 6 when I find a bad one. Same with coil packs

 

Replacing one injector is like replacing one tire. They've all had the same mileage.

Get 6 new injectors from MotorWest. It's not a hard job, but you need to replace some other gaskets along the way. Being that your mechanic just replaced a single injector, I wouldn't bet that they were on top of the other things as well. Mainly the intake gaskets, and the fuel rail crush washers.

@Timmah! has a great video on the whole process that I suggest you watch before diving in:
https://youtu.be/N-lhZIWOkyU

I had better success using the SuperLube supplied with the MotorWest Denso injectors rather than the gas in the video on the seals.

 

Thanks for all the feedback everyone! Super helpful as always - for some reason I didn’t think I’d have to replace all of them at the time and now I’m paying for it do it right or do it twice I guess…..

Will go ahead and order those injectors then and follow the video @6
Andy01DblCabTacoma posted.

Thanks again all!

 

One going is one thing, I don't necessarily disagree with having just done the one then. This time it's a pattern, knock em all out and be done with it plus the purchasing peace of mind you will be doing.

 

how many of these are needed for the 3.4L 5VZE engine.

 

Timmah! does a great job of specifying the required parts for a job in the description of his videos. But you can also find these things in the FSM or the Toyota parts catalogs:


There are 6 crush washers. He also suggests replacing an o ring on the FPR, and I've also underlined the o rings for the injectors. It's helpful to get a few extra of those incase you fubar the installation of some of them.

 

quick update: finished the install over the weekend (new set of motorwest injectors/gaskets/new o-rings, new PCV valve & grommet too) and cruised the truck around today running errands. issue is gone and truck runs absolutely tits, could not be more stoked.

huge thanks to everyone, and thank you @Andy01DblCabTacoma for linking me to that video - timmy is the man. made the install a breeze