Multiple Issues - starting with Fuel Injector - need help please!!

I am sure there are tons of threads about this, but I can't seem to find them. So I will tell my story - even the parts where I just did stupid stuff. Truck is a 2007 Tundra SR5 5.7L.

To start - I was going through replacing old parts one by one. I had a CEL, code was P0031, but there were a couple of other random codes too that I can't remember now. I researched, and was reading where the particular combo of codes usually meant it wasn't the O2 sensor, but a fuel injector messing up. I'd ran FI cleaner through and nothing helped, so I decided to pull the injectors and clean them by letting them soak in a little seafoam to break stuff up then soak in gas to dilute residual seafoam. That's obviously the dumb part. I did find that 1 of the injectors was missing the plastic pittle cap on the end. I couldn't be sure if I knocked it off into the injector port, if it had been gone for a while and that was what was causing the codes, or if i knocked it off and it fell down somewhere and i couldn't see it. I did know, though, that at least that FI needed to be replaced. And since you have to remove all 4 from 1 side to change even 1, I might as well replace all 4. And since i was replacing half of them, i might as well replace all of them.

Which meant going to the dreaded RockAuto for remanufactured injectors. It was going to take 2 weeks to get them, so I decided I might as well put everything back together in the meantime so I would at least be able to use it. It was running fine prior to me messing around with it, so I figured it would run fine after.

it did not. It sputtered and smoked and raised heck and was not happy with me at all. And that was just idling. The nastiest smelling white smoke came out of the tail pipe. It did not smell like unburnt fuel. It was rough. It really smelled like bad decisions and regret. So I stopped and decided to wait until the replacement injectors came in. That should fix it all.

It took them several tries to send me the right injectors, but I finally got them( this has been about a 3 week endeavor so far). I replaced them all and was ready to go. I should also mention that when I removed the injectors the first time- pretty much every retention clip on the wiring harness broke from being brittle. I mean the clips that click on to hold the harness clip to the injector. Everything I read said that it wasn't a problem, that the fuel rail pushing down holds enough pressure to keep them in place on the injector. So there's that.

Got it all buttoned back up - and it sputtered and spewed and raised heck and was still not happy with me. It would still puff out white smoke when I tached it to about 1500, but now it was clearly smelling like unburnt fuel. I was getting tons of various codes, the main one was still P0031, and now P0300. I'd already purchased both downstream O2 sensors, was just waiting to put them on. So I went and bought the 2 upstreams and replaced all 4.

No more P0031.

But then it was P0300 - random/multiple cylinder misfire. That makes sense - if the cylinders aren't firing, its not going to burn the gas, its going to rough rough and its going to puff white smoke. But why?

I thought maybe all that seafoam to start with fouled my plugs. So I went and replaced all of the plugs.

Same thing. I am at my whits end. I've cleared the codes, unhooked the battery and left sit for a few hours to clear the MCU. Started up and it ran rough, obviously missing. When I would tach it to 1500, it would throw these codes:

P0300 - random/multiple cylinder misfire detected
P0502 - Vehicle Speed Sensor A voltage low
P0706 - Transmission Range sensor A circuit ranger performance
P0908 - Gate Select Position Circuit Intermittent

This was from park - I never put it in gear. I did this multiple times and would get these same 4 codes each time. Sometimes, the skid control light would come on and VSC Off would flash (which i understand is a bad thing, but it would only do that like 1 out of 10 times.) I probably cleared and checked these codes 50 times trying to diagnose.

Does any of this make sense? Does anyone have an idea what I've done, or what I am missing?

 

Any change you got the injector plugs in the wiring harness backwards? One side is powered by battery, the other side is the trigger to the ECM, it grounds the trigger side to fire the injector.

If you have the plug backwards you would be feed 12V into the ECM ground circuit which could cause it to do very weird things. I would make sure all of these are correct first

 

One thing that Toyota does pretty good (I think) is make the electrical connections ID10T error proof. They are slotted so they can only go on one way, and the way the harness is attached to the rail you can't get them on the wrong injector. But I have a rare ability to muck up the unmuckable.... So I did triple check just now and they are all on correctly.

 

Did you check every single fuse in the truck. Engine fuse box and interior fuse box? Seems to me something weird if going on with communications/power to modules.

The abs, speed sensor, transmission range selector, codes are weird as you have never moved the truck from park yet it is still thinking there is a problem.

 

Working on checking fuses now. I thought maybe I knocked some connection loose on the main harness - spent 2 hours this morning with my magnifying glasses and a flashlight going over every inch.... No loose electrical or vacuum. So now, on to check 47 million fuses.

 

All fuses are good. Got a better code reader and the random misfires are 2,6,and 8. All one side, which is odd to me.

 

Have you checked for spark on 2,6,8. Still need to verify it is actually an ignition issue and not a fuel issue.

 

I will check spark in a few. I didn't initially because it ran fine until I introduced the series of problems by replacing all the injectors. I just pulled the fuel rail and injectors on that bank, figured I'd double check to make sure they were all snug. I found that one of the connector pins inside the #8 injector was broken and remained in the harness when I removed it. So that explains #8 misfire, just not 2 and 6

 

Now it's misfiring 5 and 6. At idle it's just 6, at 1500 rpm 5 joins in. But never before has 5 shown up.

Firing order is 1-8-4-3-6-5-7-2.

Could the #5 misfire be caused by #6 misfire? Lime maybe the ecm is trying to do something with timing to compensate and it throws off 5 too? Sinces it's next in firing order? Grasping at straws.

 

Solved(ish): out old injectors back on bank 2 where all the original misfires were. No more CEL, even idle, etc. - so the problem was the (new) remanufactured injectors. Existing problem: extremely low idle ( like 400, almost to a stall). Reader data stream shows bank 1 trim a lot higher than bank 2 , so I figure I just need to put my old injectors back on that side too. Also it could be that I have powered down the system and reset everything so many times that the ecm just needs run time to reclacumate everything out.

Now I know people will say " yup, you shotgun'ed it and spent a bunch on parts you didn't need too". That's true. But in my defense - replacing all of the O2 sensors and plugs were on my list of maintenance items anyway, so I wasn't really out anything more than I was already going to be. I'll just have to pony up for a quality injector to replace the one that is legit browen that sort of kick started this whole thing.

Thanks everyone for helping me and letti g me talk through it.