93 FZJ 80 losing power on highway above 2000 RPM

[Squash]

Might just be the coolant sensor for engine management.
Cruiser's have two...the one closest to the front is purely for the gauge. The one you want is closest to the fire wall.
A deep 14mm socket helps, be gentle with the wiring.

 

[gummycarbs]

PM going up and down and vehicle jerking . When applying gas slowly below 2000 RPM it rubs fine between 30-50 mph.

Sounds like a much more severe version of something I experienced. On long, uphill highway stretches I was losing power and felt a surging strong enough that I could feel the passenger seat shaking back and forth. No CEL.

I replaced the throttle position sensor with an NTK from RockAuto. Fixed the power and surge. Within two months, I start seeing an intermittent miss and got a CEL for the TPS. Replaced the NTK TPS with a used genuine Toyota TPS off eBay. No more problems. That was last summer.

 

[Fraidenburg]

Found my problem. Strainer was clogged and tank has a lot of sediment in it. Cleaned most of it but I need to drop the tank and wash it out. After a new strainer and cleaning out most of the sediment, it runs great.

 

[bpenn1980]

Solved: Mine was moisture in the TPS

@Tony George did you figure out your problem? Mine just did the same and this is the first thread describing something that sounds that same.

Will rev smooth up to 2000-2200rpm, then falls to ~1400rpm, and if I leave the pedal in the same spot it will climb back up before it falls again. No jerky, rough or dirty feeling, just very simple like a feedback loop is resetting something.

I took a video because it is pretty interesting:
New video by Brad Pennington - https://photos.app.goo.gl/qkM7sfw7qpCqHDkh9

The only other weird thing is that after the dropping rpms fault happens it will idle real low at 200rpm, but then "relearns" and will idle back up to 600rpm if I let it sit a minute or two.

I got code 26 and 71.

I think @Squash nailed it with the ECT sensor (though mine seemed in resistance spec'ish) but I ordered new O2 sensors (also in spec'ish) as well since its been ~14 years, and a new fuel pump relay to appease @landtank

Boom goes the parts cannon!!

Lastly, @Fraidenburg I replaced my fuel pump, tank filter/strainer, fuel filter, etc a couple months ago as PM so I think this is a different issue unfortunately/fortunately (?)

 

[Therealtotodile]

Hello fellas
93 FZJ 80 losing power on HWY when accelerating since 2000 RPM. RPM going up and down and vehicle jerking . When applying gas slowly below 2000 RPM it rubs fine between 30-50 mph. On idle if I try to bring RPM above 2000 it goes right back down. No CEL. No starting issues. Any ideas would be appreciated. Thanks.

Hey are you still on mud? Curious if you resolved this. My 93 doing the same thing under load above 2k rpms after I drive it nice and far; something like 100+ miles. Have a new fuel pump relay in, which was an issue I dealt with, have completely redone fuel system in the process. And this only happens after the truck is very very hot from driving. Does not occur on my daily to and from work which is like 15 miles each way. My only thing I’m going to try is cats, but it’s hard to know with no CEL and only happening every couples months. Hope you are well and could share some knowledge!