50mph + 6th gear = herky jerky... common?

I tried 89 some time back...didn't see any change except higher cost per gal. With 93 its definitely worse. I had best performance and fuel economy with the E87.....truck doesn't buck at those low rpm and the climbs the same hills without hunting. It'll go from 22.1 mpg to 23+ mpg. Those who say this truck runs best on 93 must have a different tune.

 

Bought MT for fun... mid-life crisis I guess.
Then there's left knee surgery and my need to eat dairy queen while driving.
Obvious move back to 6AT for me... getting older and lazier.
MT was fun, but AT more practical.

 

If I read Op's replies correctly, it can be reproduced without being in cruise control, correct?

 

Yes, that's right. It's only at that sweet spot though, ~50mph in 6th with light acceleration.
If it downshifts it's fine, and if I get above like 55mph it's fine.
Just seems like the engine is lugging and runs rough at that spot in 6th gear.

 

Just to reiterate, Toyota does not recommend the use of high ethanol fuels which have a lower BTU output at the equivalent octane of non-ethanol fuels. Your experience is not typical, nor does it make scientific sense as a regular fuel (E10 87 octane) develops fewer BTU’s per volume. And also as mentioned before, non-ethanol fuel at the same octane will produce more BTU and increase performance relatively speaking. The additional benefit to non-ethanol fuel is it burns cleaner and is less corrosive, keeping your fuel delivery system cleaner. Part of the reason for the fuel pump issues with Toyota’s stems from the pump components breaking down over time due to corrosion, which is another benefit of the use of non-ethanol fuels in Toyota vehicles.

 

A while back I stumbled upon some pdf talking about the engine and want to say that is normal at a range of about 45-50 mph. It's hard to explain the feeling, but in my own words it feels like the road is a little bumpy. I noticed it with my 2017, and either I don't with my 2020 or I'm used to it by now.

 

Yep, that's exactly the feeling. I actually thought it was the road the first time I felt it (until it downshifted).
I'm going to just assume it's normal based on some of the feedback here.
It's not a huge issue, just a bit annoying. Otherwise, everything seems great.

 

I have scoured the internet to find that info multiple times and have ended up short-handed each time. It's either the D-4S part of the engine or the Atkinson part, but still struggle to find that info again. But yeah, you don't have anything to worry about.

 

Normal! I dont know WHY?? but they made this tranny to shift to the next gear and 1200 rpm and the converter has NOT fully locked up at that rpm!! Thats what you feel! I have the same feeling!

 

Also made a USELESS 6th gear! and 2nd and 3rd ratio is to close! IMO

 

Normal. I found that my Tacoma was one of the worst vehicles to drive on the highway. Any slight incline or any wind and it would shift frantically 4-5-6-5-4. I've had the reprogram done and that improved things in the city, but on the highways it's miserable. The 4 cylinder 2 liter in the Wrangler with 8 speed is night and day compared to the Toyota powertrain. It sucks, but until Toyota throws an 8 speed in the Tacoma I think you will just have to live with it.

 

Huh? I use my 6th gear all the time. Even when i am going 40 mph, drives just fine at low rpms. You should go back to the superior truck forum.

 

Under low throttle angle, the TC is in controlled slip(a.k.a. flex lock up). If anything, you might be feeling the clutch in non-controlled slip, which have a plethora of causes.
-contaminated SLU solenoid
-coil sticking in SLU solenoid, due to high ATF temp(+200°F)
-worn bore in the valve body
-programming
-glazed TC clutch
-etc, etc, etc

Unless you're real-time monitoring, I doubt you can actually tell a bad flex lock up situation from an actual shift; especially in the higher gear band.

 

I ran E10 fuel in my 01 tundra for 19 years and nearly 300k miles with no fuel pump issues. You think if that were the case i'd surely have bad fuel pumps. When i sold the truck it still ran great. I even un the same gas in all my power equipment....never had any problem either.

 

ECT mode should help somewhat. As soon as I get in my truck I push the ECT button, it’s a habit for local driving 35-55 mph, transmission shifting is much better. On the intestates at 65-75 mph I turn it off and typically run cruise. If I have a lot of steep hills I might turn it back on. Also my shifting improved after 1000-1500 miles or so.

 

Mine does the same thing around 47-50 and I never use cruise control. The truck always wants to shift into 6th at that speed in my 2019 so I always punch it so it'll shift so it doesn't "chug" it feels like the drive shaft/engine are kind of shaking. I've never used the ECT button but I'm going to try it tomorrow. I use 88 gas and I'm going to try 85 when I gas up tomorrow.

 

He did say, "part of the reason"...

AFAIK, fuel pump impellers were exposed to a drying solvent which lead to cracking and absorption of fuel and eventual failure.

 

Yep. Exactly. With the cruise off I do the same thing to make it downshift.
Seems like such an easy thing for Toyota to have programmed out, but it must have been to get that extra .001gpm...

 

Totally different fuel system

Totally different fuel system on your 01 Tundra. There are numerous studies that show that with the increasing content of ethanol in fuels, the conductivity and ability of fuel to absorb water increases, and the resulting fuel is more corrosive.

See the following peer reviewed article as an example of findings:
Energy Fuels 2017, 31, 10, 10880–10889
Publication Date:August 28, 2017
https://doi.org/10.1021/acs.energyfuels.7b01682
Copyright © 2017 American Chemical Society