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Does this happen regardless of how you come into throttle?

Meaning, can you ease through or smash through it?

What intake tube are you using?

Too short a tube can allow turbulence back to the afm.
 
I can blip the throttle without a load on the engine and use the clutch to take off without a stumble. Low throttle opening under load is the worst. You can't lug the engine. 4th gear maintaining cruising speed at 2000 RPM with the auto was really bad. Mashing the throttle when its missing makes it buck worse and it has no power at all. easing through the bad spot is better.

I am using an aftermarket tube, but a copy of the stock one with the resonator ports blocked off. I am not using the PS vacuum valve and the 96 T-100 has an electronic fuel pressure regulator VSV, so the ported vacuum ports are not used and are plugged. Same problem with the stock tube. Using the stock airbox as well.
 
I re-read you post a couple times in an attempt to offer something useful. You've done more diagnostic work on the problem than the vast majority of people could. Are all of the components from the same year vehicle (PCM, harness, engine, sensors)? I first thought you had bad PCM, but you swapped that out. There is certainly a sensor to PCM communications problem because you should be getting misfire codes and you're not. Are you sure the wiring is all good? Good luck with this; hope you find a solution before our great summer / fall weather goes away.
 
So i agree that it sounds like you have done a thorough diag.

So two last things?
Who did the conversation harness? (even though its a bit of a reach)

The cam and crank sensor use that ground shield in the wiring. Double check that something weird isn't going on there.

Lastly, any possibility the alternator is giving up diodes and putting off interference?
 
Thanks for the suggestions.

The alternator is putting out 0.0v AC, but I have not disassembled and checked each diode. I thought of that being so close to the ckp wires, which WERE replaced with just regular wires. I replaced them with a twisted pair I had, but I didn’t have a 30” shielded wire on hand. I have since replaced the entire harness with the manual trans and it has intact wires to the ckp. Obd dlc shielded wire is also all correctly wired.

i did the conversion harness. I happened to end up with the same years/models as the Monch’s excellent thread on Yotatech. I had done the auto harness as well. that was entirely different so I spent a lot of time with the wiring diagrams. This set up is the Trans and transfer, pcm, harness, afm, throttle body, cmp and knock sensors from a 96 t-100 on a 97 4runner 3.4 in a 88 body.
 
I almost put the whole t-100 engine in together, but I wouldve had to do a ton of stuff I had done to the 4runner motor. timing belt, seals, oil pan, water pump, hoses, etc.

so it could still be something mechanical, except it didn’t do it when I drove the 4runner home 300 miles, and I can’t think what it might be.
 
hopefully you got the new injectors, coils and plugs from a Toyota dealer. There are a lot of fake Toyota parts out there these days, especially those three parts.
 
Fixed.

liveoak had the answer. I put in new aftermarket injectors. $75 for a set vs $200 each from Mr. T. In my head I’d already changed those So it wasn’t the problem, but he made me look at the dates. I put in the injectors when it had a hard miss. It fixed the miss. The stumble wasn’t very noticeable when it was running on 5. It had to be something else. Then I chased everything else for 6 weeks. I even took those injectors out and cleaned them in case some crud had got in them.

put in some used ones and it cleaned right up. Now I gotta get loud with the injector vendor to get the new ones refunded. Cost me 6 weeks and a ton of work. Good news is everything else is in top shape now.
 
It’s a pretty great truck now. Highway is no problem. Still loves to bomb down back roads. Getting close to 20 mpg.

it does help to have the 3.0 drivetrain when doing this. I’m using the 3.4 bell housing, and the slave is right next to the exhaust. I heat wrapped the exhaust and the slave and flushed with DOT 5.1. I was boiling the fluid on the highway, but not now. The correct fix is to swap bellhousings, but they are hard to find. I’ll probably end up with a whole trans.
 
Gumby said:
It’s a pretty great truck now. Highway is no problem. Still loves to bomb down back roads. Getting close to 20 mpg.

it does help to have the 3.0 drivetrain when doing this. I’m using the 3.4 bell housing, and the slave is right next to the exhaust. I heat wrapped the exhaust and the slave and flushed with DOT 5.1. I was boiling the fluid on the highway, but not now. The correct fix is to swap bellhousings, but they are hard to find. I’ll probably end up with a whole trans.
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That's great to hear that you got it fixed. It's always tough when the problem turns out to be a new part that you've replaced. Good thing you had a used set of injectors on hand to test.
 
Rear quarters are done about well as I can and in primer until its warm enough to paint.

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