Starts and idles but bogs when with throttle

Hello all, I’ve very much appreciated all the help to others on here as it’s helped me tremendously over the years to keep my truck/house moving through the americas

This is my first time posting though, and I really need some help. I’m pretty stumped and really need to get this thing back on the road.

I have a 5vz-fe that starts up and idles, but when I give it throttle it completely bogs. This is just parked, not under load at all, so not even enough power to get it to roll. I have an OBDII reader but it’s not throwing any codes.

It was running fine, and I changed out the plugs, then went to fire it back up and it’s been this way since.

I checked all around the igniter and the wires connected to the intake but it doesn’t seem like any of them got pulled or pinched or anything.
I’ve checked all the grounds and they all seem good.
I couldn’t find any vacuum leaks.
It has spark.
It has power to the coils.
It has new plugs, wires, and coils.
A year or so ago I did the injectors, fuel pump and filter.
And six months or so ago I did the timing belt, water pump and valve cover.

But I think all those things are chasing the wrong tail. This started immediately after changing out the plugs, and it is super consistent. It didn’t start happening over time. It doesn’t come and go or get better or worse, so this leads me to believe that it has to be something that happened when I swapped out the plugs, like a wire pulled from the igniter or something is hooked up wrong etc. but everything is all correct, according to other threads on here anyway.

I really need some help here. I would appreciate any and all thoughts or ideas about this.

Thanks a bunch

https://youtu.be/DPeuNZo3GAM?feature=shared

P.S. over the past few months it would intermittently (very slightly) bog giving it too much gas on hills, seemingly only if it had sat for a bit and then would get better as the day went on and bedriving perfect with full power. But this was VERY subtle, and not that common, and if I kept the rpm’s in the middle range I could drive no problem and prevent it from happening at all, just a bit slower up hills. What’s happening now is 100% failure of power, so totally different. Also, it was throwing p0171 after starting to drive after the engine had been shut off, pretty much everytime, but I assume it’s just from old rusted exhaust and o2 sensors. I just reset it right away and doesn’t come back on again until I park and turn off the engine and wait and then start it and get driving down the road again, then comes back on, and I repeat, with no issues at all. None of this probably matters but I thought I should mention it since it is a somewhat related system issue, and I want y’all to have all the info possible, relevant or not.

 

Welcome from Denver!


Is the fuel filter bad?

 

It shouldn’t be. Toyota lists it as a lifetime part, and a put e new oem one in anyway a little over a year ago trying to diagnose a different issue. Also I believe that would start to go over time, and not all at once while i happen to be swapping out the plugs…

 

Is there a smell of fuel?

 

When and where specifically should I check for that? the plugs smell of fuel when I pull them after running the engine and trying to rev it. Which makes sense given how it’s acting, but I still can’t figure out why it’s acting that way. It feels like the plug wires are in the wrong place or something, but I’m pretty sure they’re not

 

Sounds like a leak in the air intake. Check for any loose connections around the air intake hose that runs from the MAF to the intake plenum. You removed this when you changed your plugs, right?

 

Yeah, it kinda does seem like something like that, but I’ve checked and re-checked and even have a newer air intake on it now too.
Yes I removed that to do the plugs etc. I’ve taken it off and on dozens of times over the last couple weeks checking and replacing things trying to figure this out. Always being very careful about the wires and harness connections at the igniter, and maf sensor, and re-checking them everytime too.

I still can’t find any air leaks in the intake nor any vacuum lines.

Also it still isn’t throwing any codes

 

Plugged cat. If it idles smoothly then the exhaust is partially plugged due to the matrix breaking down. It'll pass enough exhaust gas at idle but can't above idle.

If it's not that then you jumped the belt on a cam.

 

Ok, I fiiiinally figured out how to add a video. I just added it at the bottom of the original post, please scroll up and have a look at that and lemme know what y’all think

 

Since this occurred just after changing the plugs, all bets are on something that changed during that process. Going through the plug changing process (actually doing it) once more step by step may provide insight. You may have already done this, though.

 

Wouldn’t a plugged cat be slowly getting worse over time though? and probably throwing codes? this was running fine, turned it off, changed plugs and has been like this upon startup, or am I missing something there?

 

Yes I agree, but I’ve done it many many times over now

 

I might be missing something very obvious here, but I don’t see how the belt could come off a cam while not driving, or even running, just while swapping something else out. It’s not making any sounds like that though, I’d think I would hear the belt clanging around in there, no?

I uploaded a video in the original post, check that if you can and lemme know

 

I added a video of it in the original post, if you have the time scroll up and see if that tells you anything, thanks a bunch

 

Belts or chains often jump timing when the engine is started. It's why you often hear complaints of ''it ran perfectly fine when I shut it off.'' Because, it DID run fine until it was turned off.

 

Not always. I had a 1998 GMC Sonoma [2.2] that went from running fine, no codes, to couldn't even get to 55 MPH in s plit second when a piece of the matrix of the cap plugged the exit. One new cat later and I put another 40K on it before I sold it.

If you SLOWLY open the throttle, what happens?

 

Not likely. This only happens if the belt or chain is severely stretched, which means rarely or never for those of us who take care of our vehicles. Even if it happened, a one or two tooth jump would not result in the symptoms described by the OP. The truck would still be drivable but not well. Probably throw a few codes as well.

 

I also did the timing belt less than a year ago, which makes that probably less likely as well I’d think

 

Have you checked all your fuses?
Perhaps tweaking the throttle to force it to run rough will eventually cause a code to show up.

Clutching at straws here.

 

I didn't like the little backfire back through the air filter. I couldn't hear it idle well but it didn't seem to be very smooth or maybe it was just the fan moving air.